Merge pull request #7084 from libgit2/ethomson/v1.9.1

Merge pull request #6990 from libgit2/ethomson/ci

Merge pull request #6936 from libgit2/ethomson/v1.8.4

libgit2 v1.8.4

Merge pull request #6931 from libgit2/ethomson/v1.8.3

Merge pull request #6830 from libgit2/ethomson/v1.8.2

libgit2 v1.8.2

Merge pull request #6830 from libgit2/ethomson/v1.8.2

libgit2 v1.8.2

Merge pull request #6817 from libgit2/ethomson/v1.8.1

libgit2 v1.8.1

Merge pull request #6767 from libgit2/ethomson/v18

Release v1.8

v1.7.2: update version numbers

v1.6.5: update version numbers