Unleash more matrix attempts

.drone.yml

@@ -5,28 +5,28 @@ name: default
 
 matrix:
   include:
-    - PY: 3.6
-      TOXENV: py3
-    - PY: 3.7
+    - IMAGE: 3.6-stretch
+      TOXENV: py36
+    - IMAGE: 3.7-stretch
       TOXENV: py37
-    - PY: 3.8
+    - IMAGE: 3.8-buster
       TOXENV: py38
-    - PY: 3.8
+    - IMAGE: 3.8-buster
       TOXENV: lint
-    - PY: 3.8
+    - IMAGE: 3.8-buster
       TOXENV: sort
-    - PY: 3.8
+    - IMAGE: 3.8-buster
       TOXENV: format
-    - PY: 3.8
+    - IMAGE: 3.8-buster
       TOXENV: type
-    - PY: 3.8
+    - IMAGE: 3.8-buster
       TOXENV: docs
-    - PY: 3.8
+    - IMAGE: 3.8-buster
       TOXENV: metadata-release
 
 steps:
   - name: Run tox testing
-    image: python
+    image: "python:${IMAGE}"
     commands:
       - pip install tox==3.14.6
-      - tox -v
+      - tox -e "${TOXENV}"