Extract rubocop to a separate job in CI

.gitea/workflows/tests.yml

@@ -24,7 +24,6 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
       - uses: ruby/setup-ruby@v1.207.0
       - run: bundle install
-      - run: bundle exec rubocop --force-exclusion --parallel
       - name: Wait until Postgres is ready to accept connections
         run: |
           apt-get update && apt-get install -f -y postgresql-client
@@ -42,3 +41,12 @@ jobs:
       - name: Clean up containers generated by this flow
         if: failure()
         run: docker ps --filter network=$JOB_CONTAINER_NAME-$GITHUB_JOB-network --filter name=$JOB_CONTAINER_NAME-* --format "{{.ID}}" | xargs docker rm -f
+  rubocop:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+      - uses: ruby/setup-ruby@v1.207.0
+      - run: bundle install
+      - run: bundle exec rubocop --force-exclusion --parallel