Thanks for your work on this library.

Due to GHSA-wxmh-65f7-jcvw the minimum version for the 1.x version of guzzlehttp/psr7 should be 1.9.1. This means the entry in composer.json should be:

"guzzlehttp/psr7": "^1.9.1||^2.2.1"

Is this something you are likely to change and issue a release for?