Update lint script

package.json

@@ -30,7 +30,7 @@
     "scripts": {
         "test": "jest --coverage -u && npm run lint",
         "coverage": "cat coverage/lcov.info | coveralls",
-        "lint": "eslint src/**/*.ts",
+        "lint": "eslint --ext=js,ts src",
         "format": "prettier --write '**/*.{ts,md,json}'",
         "build": "tsc",
         "prepare": "npm run build"