devel/libgit2: Update to 1.0.1
Changes: https://github.com/libgit2/libgit2/releases/tag/v1.0.1
Changes: https://github.com/libgit2/pygit2/blob/v1.2.1/CHANGELOG.rst#121-2020-05-01
Approved by: mfechner (maintainer)
Differential Revision: https://reviews.freebsd.org/D25341