chore(deps-dev): Bump guzzlehttp/psr7 in /plugins/faustwp (#2442)

Bumps [guzzlehttp/psr7](https://github.com/guzzle/psr7) from 2.11.0 to 2.12.1.
- [Release notes](https://github.com/guzzle/psr7/releases)
- [Changelog](https://github.com/guzzle/psr7/blob/2.12/CHANGELOG.md)
- [Commits](guzzle/psr7@2.11.0...2.12.1)

---
updated-dependencies:
- dependency-name: guzzlehttp/psr7
  dependency-version: 2.12.1
  dependency-type: indirect
...

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