Update getsentry/action-github-app-token action to v4

Author: renovate[bot]

.github/workflows/ack.yml

@@ -13,7 +13,7 @@ jobs:
         fetch-depth: 0
     - name: Generate token
       id: generate_token
-      uses: getsentry/action-github-app-token@v3
+      uses: getsentry/action-github-app-token@v4.0.0
       with:
         app_id: ${{ secrets.APP_ID }}
         private_key: ${{ secrets.PRIVATE_KEY }}