feat: support for guzzle 8

[VincentLanglet]

Description

Documentation

Does this require changes to the WorkOS Docs? E.g. the API Reference or code snippets need updates.

[ ] Yes

If yes, link a related docs PR and add a docs maintainer as a reviewer. Their approval is required.

Ref:

• https://github.com/guzzle/guzzle/blob/8.0/UPGRADING.md
• Remove response access from RequestException guzzle/guzzle#3532
• Remove exception handler context guzzle/guzzle#3544

[greptile-apps]

Greptile Summary

This PR extends the SDK’s HTTP transport compatibility to Guzzle 8.

• Allows Composer to resolve either Guzzle 7 or Guzzle 8.
• Uses the Guzzle 8 response and timeout exception types while retaining guarded compatibility with Guzzle 7 methods.
• Preserves API-error mapping, retry handling, and transport-timeout classification across supported versions.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains; the previously reported unconditional calls to Guzzle exception methods are now replaced with Guzzle 8 exception types and guarded Guzzle 7 compatibility paths.

Important Files Changed

Filename	Overview
composer.json	Expands the supported Guzzle dependency constraint from version 7 to versions 7 or 8.
lib/HttpClient.php	Reworks response and timeout exception inspection to avoid calling methods removed in Guzzle 8 while retaining Guzzle 7 compatibility.

_{Reviews (2): Last reviewed commit: "Add BC layer" | Re-trigger Greptile}

[VincentLanglet]

I saw you opened/merged recently @gjtorikian ; could you approve the workflow ?