Bump the npm_and_yarn group across 1 directory with 4 updates

Bumps the npm_and_yarn group with 3 updates in the / directory: [follow-redirects](https://github.com/follow-redirects/follow-redirects), [postcss](https://github.com/postcss/postcss) and [10up-toolkit](https://github.com/10up/10up-toolkit/tree/HEAD/packages/toolkit).


Updates `follow-redirects` from 1.15.3 to 1.15.6
- [Release notes](https://github.com/follow-redirects/follow-redirects/releases)
- [Commits](follow-redirects/follow-redirects@v1.15.3...v1.15.6)

Updates `postcss` from 7.0.39 to 8.4.31
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@7.0.39...8.4.31)

Updates `10up-toolkit` from 5.2.2 to 6.0.0
- [Release notes](https://github.com/10up/10up-toolkit/releases)
- [Changelog](https://github.com/10up/10up-toolkit/blob/develop/packages/toolkit/CHANGELOG.md)
- [Commits](https://github.com/10up/10up-toolkit/commits/10up-toolkit@6.0.0/packages/toolkit)

Updates `webpack-dev-middleware` from 5.3.3 to 5.3.4
- [Release notes](https://github.com/webpack/webpack-dev-middleware/releases)
- [Changelog](https://github.com/webpack/webpack-dev-middleware/blob/v5.3.4/CHANGELOG.md)
- [Commits](webpack/webpack-dev-middleware@v5.3.3...v5.3.4)

---
updated-dependencies:
- dependency-name: follow-redirects
  dependency-type: indirect
  dependency-group: npm_and_yarn-security-group
- dependency-name: postcss
  dependency-type: indirect
  dependency-group: npm_and_yarn-security-group
- dependency-name: 10up-toolkit
  dependency-type: direct:development
  dependency-group: npm_and_yarn-security-group
- dependency-name: webpack-dev-middleware
  dependency-type: indirect
  dependency-group: npm_and_yarn-security-group
...

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