ci: Add luacheck ci job (#317)

* Add luacheck ci job

* Fix most of the linting issues

* fixup: lint

Co-authored-by: TJ DeVries <devries.timothyj@gmail.com>

.github/workflows/lint.yml

@@ -0,0 +1,19 @@
+name: Linting and style checking
+
+on: [push, pull_request]
+
+jobs:
+  luacheck:
+    name: Luacheck
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Prepare
+        run: |
+          sudo apt-get update
+          sudo apt-get install luarocks
+          sudo luarocks install luacheck
+
+      - name: Lint
+        run: sudo make lint