update luacheck

.github/workflows/luacheck.yml

@@ -1,15 +1,10 @@
 name: luacheck
-
 on: [push, pull_request]
-
 jobs:
   build:
-
     runs-on: ubuntu-latest
-    timeout-minutes: 10
-
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@master
     - name: apt
       run: sudo apt-get install -y luarocks
     - name: luacheck install