chore(deps): update dependency eslint to v5.15.0 (#464)

Author: renovate[bot]

package-lock.json

@@ -43,7 +43,7 @@
     "cross-env": "5.2.0",
     "css-loader": "2.1.0",
     "cssnano": "4.1.10",
-    "eslint": "5.14.1",
+    "eslint": "5.15.0",
     "eslint-config-wordpress": "2.0.0",
     "eslint-plugin-jest": "22.3.0",
     "eslint-plugin-jsx-a11y": "6.2.1",