chore: release 3.7.3 (#275)

🤖 I have created a release \*beep\* \*boop\*
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### [3.7.3](https://www.github.com/googleapis/nodejs-secret-manager/compare/v3.7.2...v3.7.3) (2021-06-30)


### Bug Fixes

* **deps:** google-gax v2.17.0 with mTLS ([#273](https://www.github.com/googleapis/nodejs-secret-manager/issues/273)) ([9988608](https://www.github.com/googleapis/nodejs-secret-manager/commit/9988608f48b46485d0f5177f2a2e02e5997528cf))
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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).

Author: release-please[bot]

secret-manager/package.json

@@ -14,7 +14,7 @@
     "test": "c8 mocha --recursive test/ --timeout=800000"
   },
   "dependencies": {
-    "@google-cloud/secret-manager": "^3.7.2"
+    "@google-cloud/secret-manager": "^3.7.3"
   },
   "devDependencies": {
     "c8": "^7.0.0",