build(deps): bump @docusaurus/plugin-google-gtag from 2.3.1 to 2.4.0

Bumps [@docusaurus/plugin-google-gtag](https://github.com/facebook/docusaurus/tree/HEAD/packages/docusaurus-plugin-google-gtag) from 2.3.1 to 2.4.0.
- [Release notes](https://github.com/facebook/docusaurus/releases)
- [Changelog](https://github.com/facebook/docusaurus/blob/main/CHANGELOG.md)
- [Commits](https://github.com/facebook/docusaurus/commits/v2.4.0/packages/docusaurus-plugin-google-gtag)

---
updated-dependencies:
- dependency-name: "@docusaurus/plugin-google-gtag"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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