Minor fixes and cleanup (#3)

.github/dependabot.yml

@@ -1,7 +0,0 @@
-version: 2
-updates:
-- package-ecosystem: gitsubmodule
-  directory: "/"
-  schedule:
-    interval: daily
-  open-pull-requests-limit: 20

.github/workflows/luacheck.yml

@@ -1,13 +1,10 @@
 name: luacheck
 on: [push, pull_request]
 jobs:
-  build:
+  luacheck:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@master
-    - name: apt
-      run: sudo apt-get install -y luarocks
-    - name: luacheck install
-      run: luarocks install --local luacheck
-    - name: luacheck run
-      run: $HOME/.luarocks/bin/luacheck ./
+      - name: Checkout
+        uses: actions/checkout@main
+      - name: Luacheck
+        uses: lunarmodules/luacheck@master