chore(deps): update dependency mocha to v8 (#545)

Author: renovate-bot

translate/package.json

@@ -23,7 +23,7 @@
   "devDependencies": {
     "@google-cloud/storage": "^5.0.0",
     "chai": "^4.2.0",
-    "mocha": "^7.0.0",
+    "mocha": "^8.0.0",
     "uuid": "^8.0.0"
   }
 }