chore: release 2.3.1 (#456)

🤖 I have created a release \*beep\* \*boop\*
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### [2.3.1](https://www.github.com/googleapis/nodejs-cloud-container/compare/v2.3.0...v2.3.1) (2021-06-25)


### Bug Fixes

* make request optional in all cases ([#454](https://www.github.com/googleapis/nodejs-cloud-container/issues/454)) ([65ac281](https://www.github.com/googleapis/nodejs-cloud-container/commit/65ac2813d05cf21d234e42a52b73dae2f723de0f))
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This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please).

container/snippets/package.json

@@ -14,7 +14,7 @@
     "test": "mocha system-test --timeout 10000"
   },
   "dependencies": {
-    "@google-cloud/container": "^2.3.0"
+    "@google-cloud/container": "^2.3.1"
   },
   "devDependencies": {
     "chai": "^4.2.0",