Use GH app for Codex updates

Author: ishulgin

.github/workflows/codex-update.yml

@@ -48,7 +48,16 @@ jobs:
       BRANCH: ${{ needs.check.outputs.branch }}
       VERSION: ${{ needs.check.outputs.version }}
     steps:
+      - name: Generate GitHub token
+        uses: actions/create-github-app-token@v2
+        id: generate-token
+        with:
+          app-id: ${{ secrets.RELEASE_PLZ_APP_ID }}
+          private-key: ${{ secrets.RELEASE_PLZ_APP_PRIVATE_KEY }}
+
       - uses: actions/checkout@v4
+        with:
+          token: ${{ steps.generate-token.outputs.token }}
 
       - name: Configure git user and prepare branch
         run: |
@@ -86,6 +95,8 @@ jobs:
           git push -- origin "$BRANCH"
 
       - name: Create PR
+        env:
+          GH_TOKEN: ${{ steps.generate-token.outputs.token }}
         run: |
           echo -e "[What's new](https://github.com/openai/codex/releases/tag/rust-v${VERSION})\n\n$(cat pr-body.md 2>/dev/null || true)" > pr-body.md