chore(deps): update dependency @google-cloud/storage to v6 (#66)

Author: renovate-bot

storagetransfer/package.json

@@ -16,7 +16,7 @@
     "@google-cloud/storage-transfer": "^1.2.0"
   },
   "devDependencies": {
-    "@google-cloud/storage": "^5.15.3",
+    "@google-cloud/storage": "^6.0.0",
     "aws-sdk": "^2.1073.0",
     "c8": "^7.1.0",
     "chai": "^4.2.0",