chore(deps): update dependency mocha to v7 (#308)

Author: renovate-bot

automl/package.json

@@ -24,7 +24,7 @@
   "devDependencies": {
     "@google-cloud/storage": "^4.0.0",
     "chai": "^4.2.0",
-    "mocha": "^6.2.2",
+    "mocha": "^7.0.0",
     "uuid": "^3.3.3"
   }
 }