Update peter-evans/create-pull-request action to v8

Author: renovate[bot]

.github/workflows/update_protobufs.yml

@@ -27,7 +27,7 @@ jobs:
           ./bin/regen-protos.sh
 
       - name: Create pull request
-        uses: peter-evans/create-pull-request@v7
+        uses: peter-evans/create-pull-request@v8
         with:
           title: Update protobufs and classes
           add-paths: |