build(deps-dev): bump gaxios from 7.1.5 to 7.3.0 in /docs/v3 (#5334)

Bumps [gaxios](https://github.com/googleapis/google-cloud-node/tree/HEAD/core/packages/gaxios) from 7.1.5 to 7.3.0.
- [Release notes](https://github.com/googleapis/google-cloud-node/releases)
- [Changelog](https://github.com/googleapis/google-cloud-node/blob/main/core/packages/gaxios/CHANGELOG.md)
- [Commits](https://github.com/googleapis/google-cloud-node/commits/gaxios-v7.3.0/core/packages/gaxios)

---
updated-dependencies:
- dependency-name: gaxios
  dependency-version: 7.3.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]

docs/v3/package-lock.json

@@ -27,6 +27,6 @@
     "gulp": "^5.0.1",
     "gulp-cli": "^3.1.0",
     "linkinator": "^7.6.1",
-    "gaxios": "^7.1.5"
+    "gaxios": "^7.3.0"
   }
 }