Log Message:
git: updated to 2.30.1

Git v2.30.1 Release Notes
=========================

This release is primarily to merge fixes accumulated on the 'master'
front to prepare for 2.31 release that are still relevant to 2.30.x
maintenance track.

Fixes since v2.30
-----------------

 * "git fetch --recurse-submodules" failed to update a submodule
   when it has an uninitialized (hence of no interest to the user)
   sub-submodule, which has been corrected.

 * Command line error of "git rebase" are diagnosed earlier.

 * "git stash" did not work well in a sparsely checked out working
   tree.

 * Some tests expect that "ls -l" output has either '-' or 'x' for
   group executable bit, but setgid bit can be inherited from parent
   directory and make these fields 'S' or 's' instead, causing test
   failures.

 * "git for-each-repo --config=<var> <cmd>" should not run \ 
<cmd> for
   any repository when the configuration variable <var> is not defined
   even once.

 * "git mergetool --tool-help" was broken in 2.29 and failed to list
   all the available tools.

 * Fix for procedure to building CI test environment for mac.

 * Newline characters in the host and path part of git:// URL are
   now forbidden.

 * When more than one commit with the same patch ID appears on one
   side, "git log --cherry-pick A...B" did not exclude them all when a
   commit with the same patch ID appears on the other side.  Now it
   does.

 * Documentation for "git fsck" lost stale bits that has become
   incorrect.

 * Doc for packfile URI feature has been clarified.

 * The implementation of "git branch --sort" wrt the detached HEAD
   display has always been hacky, which has been cleaned up.

 * Our setting of GitHub CI test jobs were a bit too eager to give up
   once there is even one failure found.  Tweak the knob to allow
   other jobs keep running even when we see a failure, so that we can
   find more failures in a single run.

Also contains minor documentation updates and code clean-ups.