Fix mirror protoc release github action (#43)

.github/workflows/mirror_protoc_release.yml

diff --git a/.github/workflows/mirror_protoc_release.yml b/.github/workflows/mirror_protoc_release.yml
index 6533481..68ed35e 100644
--- a/.github/workflows/mirror_protoc_release.yml
+++ b/.github/workflows/mirror_protoc_release.yml
@@ -12,6 +12,7 @@
 # Allow the pull request we create to run checks
 permissions:
   contents: write
+  pull-requests: write
   actions: write
 
 jobs: