Add LuaCheck and GitHub workflow (#5)

.github/workflows/build.yml

@@ -0,0 +1,11 @@
+on: [push, pull_request]
+name: build
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@main
+      - name: lint
+        uses: Roang-zero1/factorio-mod-luacheck@master
+        with:
+          luacheckrc_url: ""

.luacheckrc

@@ -0,0 +1,12 @@
+unused_args = false
+allow_defined_top = true
+max_line_length = false
+
+read_globals = {
+    string = {fields = {"split", "trim"}},
+    table = {fields = {"copy", "getn"}},
+}
+
+globals = {
+    "minetest", "walls", "default"
+}