Bump pygit2 from 0.28.2 to 1.2.1

Bumps [pygit2](https://github.com/libgit2/pygit2) from 0.28.2 to 1.2.1.
- [Release notes](https://github.com/libgit2/pygit2/releases)
- [Changelog](https://github.com/libgit2/pygit2/blob/master/CHANGELOG.rst)
- [Commits](libgit2/pygit2@v0.28.2...v1.2.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Author: dependabot-preview[bot]

requirements.txt

@@ -2,6 +2,6 @@ atomiclong==0.1.1
 cffi==1.12.3
 fusepy==3.0.1
 pycparser==2.19
-pygit2==0.28.2
+pygit2==1.2.1
 raven==6.10.0
 six==1.12.0