Log Message:
libgit2: Update to 1.1.0

v1.1
----

This is release v1.1, "Fernweh".

### Changes or improvements

* Our bundled PCRE dependency has been updated to 8.44.

* The `refs/remotes/origin/HEAD` file will be created at clone time to
  point to the origin's default branch.

* libgit2 now uses the `__atomic_` intrinsics instead of `__sync_`
  intrinsics on supported gcc and clang versions.

* The `init.defaultBranch` setting is now respected and `master` is
  no longer the hardcoded as the default branch name.

* Patch files that do not contain an `index` line can now be parsed.

* Configuration files with multi-line values can now contain quotes
  split across multiple lines.

* Windows clients now attempt to use TLS1.3 when available.

* Servers that request an upgrade to a newer HTTP version are
  silently ignored instead of erroneously failing.

* Users can pass `NULL` to the options argument to
  `git_describe_commit`.

* Clones and fetches of very large packfiles now succeeds on 32-bit
  platforms.

* Custom reference database backends can now handle the repository's
  `HEAD` correctly.

* Repositories with a large number of packfiles no longer exhaust the
  number of file descriptors.

* The test framework now supports TAP output when the `-t` flag is
  specified.

* The test framework can now specify an exact match to a test
  function using a trailing `$`.

* All checkout types support `GIT_CHECKOUT_DISABLE_PATHSPEC_MATCH`.

* `git_blame` now can ignore whitespace changes using the option
  `GIT_BLAME_IGNORE_WHITESPACE`.

* Several new examples have been created, including an examples for
  commit, add and push.

* Mode changes during rename are now supported in patch application.

* `git_checkout_head` now correctly removes untracked files in a
  subdirectory when the `FORCE | REMOVE_UNTRACKED` options are specified.