build(deps-dev): bump linkinator from 6.1.4 to 7.5.3 in /docs/v3 (#4725)

* build(deps-dev): bump linkinator from 6.1.4 to 7.5.3 in /docs/v3

Bumps [linkinator](https://github.com/JustinBeckwith/linkinator) from 6.1.4 to 7.5.3.
- [Release notes](https://github.com/JustinBeckwith/linkinator/releases)
- [Changelog](https://github.com/JustinBeckwith/linkinator/blob/main/CHANGELOG.md)
- [Commits](JustinBeckwith/linkinator@v6.1.4...linkinator-v7.5.3)

---
updated-dependencies:
- dependency-name: linkinator
  dependency-version: 7.5.3
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

* Add gaxios to dev deps

Gaxios used to be be a transitive dependency of linkinator but was
removed with version > 7 -> thus adding it explicitly.

---------

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: johha <[email protected]>

Author: dependabot[bot]