Update go-git dependency to get performance fixes

[filipnavara]

Go-git 4.12 (https://github.com/src-d/go-git/releases/tag/v4.12.0) was released now so Gitea should pick it up for the performance improvements.

[filipnavara]

Unfortunately the new commitgraph packages are still missing after the update (the plumbing/format/commitgraph and plumbing/object/commitgraph directories).

[zeripath]

Oh that's odd they should be there - try make vendor and see if they appear and were missed in the commit.

[filipnavara]

I cannot see them on GitHub web (for Gitea repo) so they must have been missed somewhere along the way. make vendor makes a mess on my Windows machine which is why I always ask others to do it for me.

[zeripath]

Ok they definitely should be there - but they're missing because git doesn't complain about new untracked directories. So our make vendor test will miss that they weren't added.

Could you open an issue and either myself or someone else will be able to fix the missing vendor files.

(What happens when you run make vendor?)

[lunny]

So is this a bug of go?

[lunny]

It seems plumbing/format/commitgraph and plumbing/object/commitgraph have never been referenced by other packages on go-git. Is that the reason the directories missing when vendoring?

[zeripath]

Nope I suspect the files get added when we do make vendor, but that we missed them when creating the pr and our make test-vendor case misses the fact that they're not added.

I suspect these commit graph functions are not used anywhere in go git at present so it doesn't cause compilation issues that they're not present.

[lunny]

@zeripath I have executed make vendor locally again. But it also didn't copy that two directories.

[zeripath]

So just checking quickly it doesn't appear to be fixed using make vendor. Damn.