chore: add lint command for ci

Author: daKmoR

Diff for: .eslintignore

@@ -1,2 +1,3 @@
 /coverage
 /node_modules
+/_site

Diff for: package.json

@@ -10,6 +10,7 @@
     "lit-html": "^0.12.0"
   },
   "scripts": {
+    "lint": "npm run lint:eslint",
     "lint:eslint": "eslint --ext .js,.html .",
     "site:build": "npm run storybook:build",
     "storybook:build": "build-storybook -o _site",