Bump libgit2 to 0.28.2

[nalimilan]

This is the companion to JuliaLang/julia#32806. I hope that's correct.

[staticfloat]

lgtm

[staticfloat]

https://github.com/JuliaPackaging/Yggdrasil/releases/tag/LibGit2-v0.28.2%2B0

[nalimilan]

Thanks. Looks like the build scripts expect the release to be called "-1" rather than "+0"? At least that's my interpretation of the failures at https://githvub.com/JuliaLang/julia/pull/32806.

[staticfloat]

Yes, we are transitioning from a vX.Y.Z-BUILD format to vX.Y.Z+BUILD format, as it makes version comparisons simpler. (We don't actually do any version comparisons yet, but someday we will).

You need to change this line: https://github.com/JuliaLang/julia/pull/32806/files#diff-a01ad0cac7aa5a648c5d00ec39bd9afcR100

Instead of LibGit2-v$(LIBGIT2_VER)-$(LIBGIT2_BB_REL) at the end, change it to LibGit2-v$(LIBGIT2_VER)+$(LIBGIT2_BB_REL). Then also change LIBGIT2_BB_REL to 0 instead of 1.