Add LUA linting

.drone.yml

@@ -13,8 +13,11 @@ steps:
   - cd sources && git checkout $DRONE_COMMIT
 
 - name: lint
-  image: martijnrondeel/luarocks
+  image: alpine
   commands:
+    - apk update
+    - RUN apk add --no-cache lua lua-dev luarocks
+    - which luarocks
     - luarocks install luacheck
     - luacheck sources