fix: also remove PyPy 3.10 from GitHub Actions workflow

Complete the fix by removing PyPy 3.10 from both tox.ini and the GitHub
Actions workflow. All PyPy 3.10 jobs are failing with:

  error: the configured PyPy interpreter version (3.10) is lower than
  PyO3's minimum supported version (3.11)

This is caused by the nh3 package dependency requiring PyO3 which now
requires PyPy 3.11+. PyPy 3.9 still works fine.

Removes 4 failing jobs:
- pypy310-pydantic28-cover
- pypy310-pydantic210-cover
- pypy310-pydantic28-nocov
- pypy310-pydantic210-nocov

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: jontsai

.github/workflows/github-actions.yml

@@ -91,30 +91,6 @@ jobs:
             python_arch: 'x64'
             tox_env: 'py312-pydantic210-nocov'
             os: 'ubuntu-latest'
-          - name: 'pypy310-pydantic28-cover'
-            python: 'pypy-3.10'
-            toxpython: 'pypy3.10'
-            python_arch: 'x64'
-            tox_env: 'pypy310-pydantic28-cover'
-            os: 'ubuntu-latest'
-          - name: 'pypy310-pydantic210-cover'
-            python: 'pypy-3.10'
-            toxpython: 'pypy3.10'
-            python_arch: 'x64'
-            tox_env: 'pypy310-pydantic210-cover'
-            os: 'ubuntu-latest'
-          - name: 'pypy310-pydantic28-nocov'
-            python: 'pypy-3.10'
-            toxpython: 'pypy3.10'
-            python_arch: 'x64'
-            tox_env: 'pypy310-pydantic28-nocov'
-            os: 'ubuntu-latest'
-          - name: 'pypy310-pydantic210-nocov'
-            python: 'pypy-3.10'
-            toxpython: 'pypy3.10'
-            python_arch: 'x64'
-            tox_env: 'pypy310-pydantic210-nocov'
-            os: 'ubuntu-latest'
     steps:
     - uses: actions/checkout@v4
       with: