chore(deps): update dependency webdriverio to v8

Author: renovate[bot]

package.json

@@ -39,7 +39,7 @@
     "wdio-sauce-service": "0.4.14",
     "wdio-selenium-standalone-service": "0.0.10",
     "wdio-spec-reporter": "0.1.5",
-    "webdriverio": "4.14.4",
+    "webdriverio": "8.16.4",
     "webpack": "4.33.0",
     "webpack-cli": "3.3.4"
   },