Test making CI/CD parallel

.drone.yml

@@ -3,17 +3,21 @@ type: docker
 name: test
 
 steps:
+  - name: black
+    image: pyfound/black:21.7b0
+    commands:
+      - black --check --diff --quiet .
+
   - name: test-python-3.8
     image: python:3.8-slim
     commands:
       - python test.py
+    depends_on:
+      - black
 
   - name: test-python-3.9
     image: python:3.9-slim
     commands:
       - python test.py
-
+    depends_on:
-  - name: black
+      - black
-    image: pyfound/black:21.7b0
-    commands:
-      - black --check --diff --quiet .