Install git

.drone.yml

@@ -8,8 +8,9 @@ platform:
 
 steps:
   - name: step1
-    image: busybox
+    image: alpine
     commands:
+      - apk add git
       - changed_charts=$(git show --name-only --pretty="format:" | grep '^charts' | perl -pe 's/^([^\/]*?\/[^\/]*?)\/.*/$1/' | sort | uniq)
       - echo $changed_charts