Log Message:
git: updated to 2.20.1

Git v2.20.1:

This release is primarily to fix brown-paper-bag breakages in the
2.20.0 release.

Fixes since v2.20

 * A few newly added tests were not portable and caused minority
   platforms to report false breakages, which have been fixed.

 * Portability fix for a recent update to parse-options API.

 * "git help -a" did not work well when an overly long alias is
   defined, which has been corrected.

 * A recent update accidentally squelched an error message when the
   run_command API failed to run a missing command, which has been
   corrected.