[llvm] DeveloperPolicy: Update commit access requirements (PR #127006)

[Alex Bradbury via llvm-commits]

================
@@ -539,11 +539,13 @@ What are the expectations around a revert?
 Obtaining Commit Access
 -----------------------
 
-We grant commit access to contributors that can provide a valid justification.
-If you would like commit access, please use this `link <https://github.com/llvm/llvm-project/issues/new?title=Request%20Commit%20Access%20For%20%3Cuser%3E&body=%23%23%23%20Why%20Are%20you%20requesting%20commit%20access%20?>`_ to file
+Once you have 3 or more merged pull requests, you may use this
+link <https://github.com/llvm/llvm-project/issues/new?title=Request%20Commit%20Access%20For%20%3Cuser%3E&body=%23%23%23%20Why%20Are%20you%20requesting%20commit%20access%20?>`_ to file
 an issue and request commit access. Replace the <user> string in the title
 with your github username, and explain why you are requesting commit access in
-the issue description. If approved, a GitHub invitation will be sent to your
+the issue description.  Once the issue is created, you will need to get two
+current contributors to ack your requests before commit access will be granted.
----------------
asb wrote:

I wonder if it would be uncontroversial to say something like:

"Reviewers of your committed patches will automatically be CCed upon creating the issue. Most commonly these reviewers will provide the necessary approval, but approvals from other LLVM committers are also acceptable. Those reviewing the application will confirm that you have indeed had three patches committed, and that based on interactions on those reviews and elsewhere in the LLVM community they have no concern about you adhering to our Developer Policy and Code of Conduct."

https://github.com/llvm/llvm-project/pull/127006