ci: add linter for every PR & commit (#6988)

.github/workflows/pr-lint.yml

@@ -0,0 +1,18 @@
+name: Linter
+
+on: [push, pull_request]
+
+jobs:
+  linter:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-node@v1
+      with:
+        node-version: '14'
+    - run: yarn install
+    - name: Lint
+      run: |
+        npm run lint
+      env:
+        CI: true

package.json

@@ -12,6 +12,7 @@
     "profiling": "NODE_ENV=production node --prof lib/index.js",
     "docs:dev": "vuepress dev docs",
     "docs:build": "vuepress build docs",
+    "lint": "eslint .",
     "format": "eslint \"**/*.js\" --fix && node docs/.format/format.js && prettier \"**/*.{js,json}\" --write",
     "format:staged": "eslint \"**/*.js\" --fix && node docs/.format/format.js --staged && pretty-quick --staged --verbose --pattern \"**/*.{js,json}\"",
     "format:check": "eslint \"**/*.js\" && prettier-check \"**/*.{js,json}\"",