.github: Run luacheck v1.2.0 in CI

.github/workflows/pre-commit.yml

@@ -20,3 +20,9 @@ jobs:
     - run: python3 -m pip install --upgrade pip
     - run: python3 -m pip install pytest
     - run: PYTHONPATH="." pytest tests/test_pre_commit_copyright.py
+
+  luacheck:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - uses: lunarmodules/luacheck@v1

.luacheckrc

@@ -0,0 +1,16 @@
+std = "lua53"  -- Lua 5.3 standard
+
+max_line_length = 678
+
+ignore = {
+  "111",  -- setting non-standard global
+  "112",  -- mutating an undefined global variable.
+  "113",  -- accessing undefined variable
+  "212",  -- Unused argument
+  "214",  -- used variable with unused hint
+  "611",  -- line consists only of whitespace
+  "612",  -- trailing whitespace
+  "613",  -- trailing whitespace in string
+  "614",  -- trailing whitespace in comment
+  "621",  -- inconsistent indentation
+}