chore: add linting to CI

.github/workflows/lint.yml

@@ -0,0 +1,32 @@
+name: Lint
+
+on: [push, pull_request]
+
+jobs:
+  luacheck:
+    name: Luacheck
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+
+      - name: Prepare
+        run: |
+          sudo apt-get update
+          sudo add-apt-repository universe
+          sudo apt install luarocks -y
+          sudo luarocks install luacheck
+
+      - name: Run Luacheck
+        run: luacheck .
+
+  stylua:
+    name: StyLua
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Stylua
+      uses: JohnnyMorganz/stylua-action@1.0.0
+      with:
+        token: ${{ secrets.GITHUB_TOKEN }}
+        args: --check .
+

.luacheckrc

@@ -1 +1,16 @@
 max_comment_line_length = false
+codes = true
+
+exclude_files = {
+  "tests/",
+}
+
+ignore = {
+  "212", -- Unused argument
+  "631", -- Line is too long
+  "122", -- Setting a readonly global
+}
+
+read_globals = {
+  "vim",
+}