Log Message:
libgit2: update to 1.6.0.

v1.6
----

This is release v1.6.0, "Hubbeliges Krokodil". This release adds \ 
experimental SHA256 support and includes many new features and bugfixes.

## What's Changed

### New features

* **Support for bare repositories with SHA256 support (experimental)** by \ 
@ethomson in https://github.com/libgit2/libgit2/pull/6191
   You can configure experimental SHA256 support in libgit2 with `cmake \ 
-DEXPERIMENTAL_SHA256=ON` during project setup. This is useful for considering \ 
future integrations, work on clients, and work on language bindings. At present, \ 
working with bare repositories should largely work, including remote operations. \ 
But many pieces of functionality - including working with the index - are not \ 
yet supported. As a result, **libgit2 with SHA256 support should not be used in \ 
production or released with package distribution.**

* **Support the notion of a home directory separately from global configuration \ 
directory** by @ethomson in https://github.com/libgit2/libgit2/pull/6455 and \ 
https://github.com/libgit2/libgit2/pull/6456
  Callers and language bindings can now configure the home directory that \ 
libgit2 uses for file lookups (eg, the `.ssh` directory). This configuration is \ 
separate from the git global configuration path.

* **stash: partial stash specific files** by @gitkraken-jacobw in \ 
https://github.com/libgit2/libgit2/pull/6330
  A stash can be created with only specific files, using a pathspec. This is \ 
similar to the `git stash push` command.

* **push: revparse refspec source, so you can push things that are not refs** by \ 
@sven-of-cord in https://github.com/libgit2/libgit2/pull/6362
  Pushes can be performed using refspecs instead of only references.

* **Support OpenSSL3** by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6464 and \ 
https://github.com/libgit2/libgit2/pull/6471
  OpenSSL 3 is now supported, both when compiled directly and dynamically loaded.

### Bug fixes
* winhttp: support long custom headers by @kcsaul in \ 
https://github.com/libgit2/libgit2/pull/6363
* Fix memory leak by @csware in https://github.com/libgit2/libgit2/pull/6382
* Don't fail the whole clone if you can't find a default branch by @torvalds in \ 
https://github.com/libgit2/libgit2/pull/6369
* #6366: When a worktree is missing, return `GIT_ENOTFOUND`. by @arroz in \ 
https://github.com/libgit2/libgit2/pull/6395
* commit-graph: only verify csum on `git_commit_graph_open()`. by @derrickstolee \ 
in https://github.com/libgit2/libgit2/pull/6420
* Ignore missing 'safe.directory' config during ownership checks by @kcsaul in \ 
https://github.com/libgit2/libgit2/pull/6408
* Fix leak in `git_tag_create_from_buffer` by @julianmesa-gitkraken in \ 
https://github.com/libgit2/libgit2/pull/6421
* http: Update httpclient options when reusing an existing connection. by \ 
@slackner in https://github.com/libgit2/libgit2/pull/6416
* Add support for `safe.directory *` by @csware in \ 
https://github.com/libgit2/libgit2/pull/6429
* URL parsing for google-compatible URLs by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6326
* Fixes #6433: `git_submodule_update` fails to update configured but missing \ 
submodule by @tagesuhu in https://github.com/libgit2/libgit2/pull/6434
* transport: fix capabilities calculation by @russell in \ 
https://github.com/libgit2/libgit2/pull/6435
* push: use resolved oid as the source by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6452
* Use `git_clone__submodule` to avoid file checks in workdir by @abizjak in \ 
https://github.com/libgit2/libgit2/pull/6444
* #6422: handle dangling symbolic refs gracefully by @arroz in \ 
https://github.com/libgit2/libgit2/pull/6423
* `diff_file`: Fix crash when freeing a patch representing an empty untracked \ 
file by @jorio in https://github.com/libgit2/libgit2/pull/6475
* clone: clean up options on failure by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6479
* stash: update strarray usage by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6487
* #6491: Sets `oid_type` on repos open with `git_repository_open_bare` by @arroz \ 
in https://github.com/libgit2/libgit2/pull/6492
* Handle Win32 shares by @ethomson in https://github.com/libgit2/libgit2/pull/6493
* Make failure to connect to ssh-agent non-fatal by @fxcoudert in \ 
https://github.com/libgit2/libgit2/pull/6497
* odb: don't unconditionally add `oid_type` to stream by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6499
* Pass hostkey & port to host verify callback by @fxcoudert in \ 
https://github.com/libgit2/libgit2/pull/6503

### Security fixes

### Code cleanups
* meta: update version number to v1.6.0-alpha by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6352
* sha256: indirection for experimental functions by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6354
* Delete `create.c.bak` by @lrm29 in https://github.com/libgit2/libgit2/pull/6398
* Support non-cmake builds with an in-tree `experimental.h` by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6405

### Build and CI improvements
* tests: skip flaky-ass googlesource tests by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6353
* clar: remove ftrunacte from libgit2 tests by @boretrk in \ 
https://github.com/libgit2/libgit2/pull/6357
* CI Improvements by @ethomson in https://github.com/libgit2/libgit2/pull/6403
* fix compile on Windows with `-DWIN32_LEAN_AND_MEAN` by @christoph-cullmann in \ 
https://github.com/libgit2/libgit2/pull/6373
* Fixes #6365 : Uppercase windows.h include fails build in case-sensitive OS by \ 
@Vinz2008 in https://github.com/libgit2/libgit2/pull/6377
* ci: update version numbers of actions by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6448
* thread: avoid warnings when building without threads by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6432
* src: hide unused hmac() prototype by @0-wiz-0 in \ 
https://github.com/libgit2/libgit2/pull/6458
* tests: update clar test runner by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6459
* ci: always create test summaries, even on failure by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6460
* Fix build failure with `-DEMBED_SSH_PATH` by @vicr123 in \ 
https://github.com/libgit2/libgit2/pull/6374
* Define correct `off64_t` for AIX by @bzEq in \ 
https://github.com/libgit2/libgit2/pull/6376
* Fix some warnings in main by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6480
* strarray: remove deprecated declaration by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6486
* tests: always unset `HTTP_PROXY` before starting tests by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6498

### Documentation improvements
* add 2-clause BSD license to COPYING by @martinvonz in \ 
https://github.com/libgit2/libgit2/pull/6413
* Add new PHP bindings project to language bindings section of README.md by \ 
@RogerGee in https://github.com/libgit2/libgit2/pull/6473
* README: clarify the linking exception by @ethomson in \ 
https://github.com/libgit2/libgit2/pull/6494
* Correct the definition of "empty" in the docs for \ 
`git_repository_is_empty` by @timrogers in \ 
https://github.com/libgit2/libgit2/pull/6500