Update CHANGES.md for v0.29

Author: bording

CHANGES.md

@@ -1,6 +1,16 @@
 # LibGit2Sharp Changes
 
-## v0.28
+## v0.29 - ([diff](https://github.com/libgit2/libgit2sharp/compare/0.28.0..0.29.0))
+
+### Changes
+- This release includes [libgit2 v1.7.1](https://github.com/libgit2/libgit2/releases/tag/v1.7.1).
+  - CI changes for the native binaries has removed support for CentOS 7. See [#2066](https://github.com/libgit2/libgit2sharp/pull/2066) for details.
+
+### Additions
+- Add proxy options [#2065](https://github.com/libgit2/libgit2sharp/pull/2065)
+  - See PR for details, including some  breaking changes to `CloneOptions` and `SubmoduleUpdateOptions`
+
+## v0.28 - ([diff](https://github.com/libgit2/libgit2sharp/compare/0.27.2..0.28.0))
 
 ### Additions
 - Add CustomHeaders to PushOptions [#2052](https://github.com/libgit2/libgit2sharp/pull/2052)