Bump guzzlehttp/psr7 from 1.8.3 to 1.8.4

Bumps [guzzlehttp/psr7](https://github.com/guzzle/psr7) from 1.8.3 to 1.8.4.
- [Release notes](https://github.com/guzzle/psr7/releases)
- [Changelog](https://github.com/guzzle/psr7/blob/1.8.4/CHANGELOG.md)
- [Commits](guzzle/psr7@1.8.3...1.8.4)

---
updated-dependencies:
- dependency-name: guzzlehttp/psr7
  dependency-type: direct:production
...

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Author: dependabot[bot]