chore: release 2.3.4 (#918)

🤖 I have created a release \*beep\* \*boop\*
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### [2.3.4](https://www.github.com/googleapis/nodejs-vision/compare/v2.3.3...v2.3.4) (2021-06-22)


### Bug Fixes

* make request optional in all cases ([#917](https://www.github.com/googleapis/nodejs-vision/issues/917)) ([d301b79](https://www.github.com/googleapis/nodejs-vision/commit/d301b79dee83948bada4b16e33048933d454c051))
---


This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please).

vision/samples/package.json

@@ -13,7 +13,7 @@
     "test": "mocha system-test --timeout 600000"
   },
   "dependencies": {
-    "@google-cloud/vision": "^2.3.3",
+    "@google-cloud/vision": "^2.3.4",
     "natural": "^5.0.0",
     "pureimage": "^0.3.0",
     "redis": "^3.0.0",