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

.forgejo/workflows/style.yaml

@@ -0,0 +1,23 @@
+# 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:
+  ruff:
+    runs-on: docker
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Hatch
+        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 .

CONTRIBUTING.md

@@ -21,6 +21,7 @@ The `tag` should be one of the following:
 - `test` - for adding or correcting tests
 - `style` - for changes to the linter or formatter configuration and its results
 - `docs` - for changes to documentation only
+- `ci` - for changes to the CI and its configuration
 - `other` - for anything that isn't covered by the tags above
 
 If a change is a breaking change then that should be indicated by adding a `!` after the tag.