chore(package): update eslint to version 5.15.2

Author: greenkeeper[bot]

package.json

@@ -39,7 +39,7 @@
     "@babel/core": "7.3.4",
     "@babel/preset-env": "7.3.4",
     "del": "4.0.0",
-    "eslint": "5.15.1",
+    "eslint": "5.15.2",
     "eslint-config-google": "0.12.0",
     "gulp": "4.0.0",
     "gulp-babel": "8.0.0",