[llvm] github-automation.py: Set maintainer_can_modify=True for backport PRs (PR #84819)

[Tom Stellard via llvm-commits]

https://github.com/tstellar created https://github.com/llvm/llvm-project/pull/84819

This makes it possible to rebase the branch using the Web UI, which makes it easier to manually merge the PRs.  Manual merge is required when squash merge won't preserve author information of the backport.

>From 8936387e5d860d7ab0ee4f2cf4baacd955005602 Mon Sep 17 00:00:00 2001
From: Tom Stellard <tstellar at redhat.com>
Date: Mon, 11 Mar 2024 12:56:07 -0700
Subject: [PATCH] github-automation.py: Set maintainer_can_modify=True for
 backport PRs

This makes it possible to rebase the branch using the Web UI, which
makes it easier to manually merge the PRs.  Manual merge is required
when squash merge won't preserve author information of the backport.
---
 llvm/utils/git/github-automation.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/utils/git/github-automation.py b/llvm/utils/git/github-automation.py
index b2e6843eb9af17..b21f14eca4450a 100755
--- a/llvm/utils/git/github-automation.py
+++ b/llvm/utils/git/github-automation.py
@@ -586,7 +586,7 @@ def create_pull_request(
                 body=body,
                 base=release_branch_for_issue,
                 head=head,
-                maintainer_can_modify=False,
+                maintainer_can_modify=True,
             )
 
             pull.as_issue().edit(milestone=self.issue.milestone)