add black check workflow

missing python setup step

try changing workflow name

upgrade action version

.github/workflows/black-check.yml

@@ -0,0 +1,26 @@
+# For more information on how to use this template please refer to:
+# http://tardis-sn.github.io/tardis/development/continuous_integration.html
+
+name: black
+
+on:
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Setup Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.x
+
+      - name: Install Black
+        run: pip install black
+
+      - name: Run Black
+        run: black --check tardis