ci: add a black job to the style.yaml workflow running black --check

.forgejo/workflows/style.yaml

@@ -1,6 +1,7 @@
 # Links & Resources:
 # - https://hatch.pypa.io/latest/install/#github-actions
 # - https://docs.astral.sh/ruff/integrations/#github-actions
+# - https://black.readthedocs.io/en/stable/integrations/github_actions.html
 on: push
   
 jobs:
@@ -12,3 +13,11 @@ jobs:
         uses: https://github.com/pypa/hatch@install
       - name: Run Ruff
         run: hatch run lint:ruff check --output-format=github .
+  black:
+    runs-on: docker
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Hatch
+        uses: https://github.com/pypa/hatch@install
+      - name: Run Black
+        run: hatch run lint:black --check --diff .