Update contributing.md to reference rebase and merge

Signed-off-by: Vui Lam <vui@vmware.com>

CONTRIBUTING.md

@@ -80,7 +80,7 @@ Second, a one-to-one correspondence between pull requests and commits makes it
 easier to manage reverting changes.
 
 At a maintainer's discretion, pull requests with multiple commits can be merged
-with the [Create a merge commit](https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/about-pull-request-merges)
+with the [Rebase and merge](https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/about-pull-request-merges#rebase-and-merge-your-pull-request-commits)
 option. Merging pull requests with multiple commits can make sense in cases
 where a change involves code generation or mechanical changes that can be
 cleanly separated from semantic changes. The maintainer should review commit