ci: check style

.drone.yml

@@ -5,6 +5,14 @@ type: docker
 name: default
 
 steps:
+  - name: check style
+    image: python:3.12-alpine
+    commands:
+      - pip install black isort flake8
+      - black --check .
+      - isort -c .
+      - flake8 .
+
   - name: build
     image: python:3.12-alpine
     commands:
@@ -27,3 +35,9 @@ steps:
     when:
       event:
         - tag
+
+trigger:
+  event:
+    - pr
+    - push
+    - tag