fix(deps): update dependency @google-cloud/promisify to v3 (#3604)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [@google-cloud/promisify](https://togithub.com/googleapis/nodejs-promisify) | [`^2.0.0` -> `^3.0.0`](https://renovatebot.com/diffs/npm/@google-cloud%2fpromisify/2.0.4/3.0.1) | [![age](https://badges.renovateapi.com/packages/npm/@google-cloud%2fpromisify/3.0.1/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/npm/@google-cloud%2fpromisify/3.0.1/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/npm/@google-cloud%2fpromisify/3.0.1/compatibility-slim/2.0.4)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/npm/@google-cloud%2fpromisify/3.0.1/confidence-slim/2.0.4)](https://docs.renovatebot.com/merge-confidence/) |

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packages/google-cloud-translate/package.json

@@ -52,7 +52,7 @@
   },
   "dependencies": {
     "@google-cloud/common": "^4.0.0",
-    "@google-cloud/promisify": "^2.0.0",
+    "@google-cloud/promisify": "^3.0.0",
     "arrify": "^2.0.0",
     "extend": "^3.0.2",
     "google-gax": "^3.5.2",