feat: add selene linter CI

.github/workflows/lint.yml

@@ -0,0 +1,18 @@
+name: lint
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    types: [opened, synchronize]
+
+jobs:
+  selene:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Setup and run selene
+        uses: NTBBloodbath/selene-action@v1.0.0
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          args: "lua/"