Update dependency eslint to v6.8.0 (#545)

Author: renovate[bot]

package-lock.json

@@ -42,7 +42,7 @@
     "chromedriver": "79.0.0",
     "coveralls": "3.0.9",
     "del": "5.1.0",
-    "eslint": "6.7.2",
+    "eslint": "6.8.0",
     "eslint-config-airbnb": "18.0.1",
     "eslint-plugin-import": "2.19.1",
     "geckodriver": "1.19.1",