add luacheck workflow

.github/workflows/main.yml

@@ -0,0 +1,25 @@
+name: luacheck
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+  workflow_dispatch:
+
+jobs:
+  main:
+    runs-on: ubuntu-latest
+
+    steps:
+      # Checks-out your repository under $GITHUB_WORKSPACE
+      - uses: actions/checkout@v2
+      - name: luacheck
+        uses: nebularg/actions-luacheck@v1.1.0
+        #with:
+          #files: # optional, default is .
+          #path: # optional, default is ${{ github.workspace }}
+          #args: # optional
+          #config: # optional
+          #annotate: # optional, default is none

.luacheckrc

@@ -0,0 +1,45 @@
+read_globals = {
+    "DIR_DELIM", "INIT",
+
+    "minetest", "core",
+    "dump", "dump2",
+
+    "Raycast",
+    "Settings",
+    "PseudoRandom",
+    "PerlinNoise",
+    "VoxelManip",
+    "SecureRandom",
+    "VoxelArea",
+    "PerlinNoiseMap",
+    "PcgRandom",
+    "ItemStack",
+    "AreaStore",
+
+    "vector",
+
+    table = {
+        fields = {
+            "copy",
+            "indexof",
+            "insert_all",
+            "key_value_swap",
+            "shuffle",
+        }
+    },
+
+    string = {
+        fields = {
+            "split",
+            "trim",
+        }
+    },
+
+    math = {
+        fields = {
+            "hypot",
+            "sign",
+            "factorial"
+        }
+    },
+}