fix(docs): update sphinxemoji to fix Python 3.12+ compatibility

[thanhlim]

Summary

• Update sphinxemoji from 0.2.0 to 0.3.1 in pyproject.toml
• sphinxemoji 0.2.0 uses pkg_resources which was removed in Python 3.12, causing doc builds to fail
• 0.3.1 uses importlib.resources instead

Supersedes #2111 (which included unrelated changes).

Test plan

• CI passes (doc build succeeds on Python 3.12+)

🤖 Generated with Claude Code

[thanhlim]

Opened against wrong base. Recreating against upstream main directly.

[chrisinmtown]

I cloned your repo, checked out your branch and ran tox but unfortunately that reports some failures. Here's the summary:

  py39-min: OK (44.64=setup[9.04]+cmd[0.00,9.34,2.30,0.42,23.53,0.00] seconds)
  py39-pypi: FAIL code 1 (8.17=setup[4.33]+cmd[2.13,1.71] seconds)
  py310-pypi: OK (35.65=setup[5.79]+cmd[5.09,1.47,0.44,22.87] seconds)
  py311-pypi: OK (31.98=setup[4.77]+cmd[3.30,1.34,0.42,22.15] seconds)
  py312-pypi: OK (33.59=setup[4.25]+cmd[2.96,1.35,0.42,24.61] seconds)
  py313-pypi: FAIL code 4 (15.01=setup[8.49]+cmd[3.18,1.42,0.44,1.48] seconds)
  py314-pypi: FAIL code 1 (28.60=setup[4.72]+cmd[2.28,21.60] seconds)
  pre-commit: OK (16.40=setup[2.96]+cmd[13.44] seconds)
  evaluation failed :( (214.09 seconds)

Here's the Py313 error:

py313-pypi: commands[3]> poetry run python -m pytest tests --cov connexion --cov-report term-missing
ImportError while loading conftest '/Users/me/git/github/connexion/thrivemarket/connexion/tests/conftest.py'.
tests/conftest.py:5: in <module>
    from connexion import AsyncApp, FlaskApp
connexion/__init__.py:10: in <module>
    from .apps import AbstractApp  # NOQA
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
connexion/apps/__init__.py:6: in <module>
    from .abstract import AbstractApp  # NOQA
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
connexion/apps/abstract.py:9: in <module>
    from starlette.testclient import TestClient
.tox/py313-pypi/lib/python3.13/site-packages/starlette/testclient.py:25: in <module>
    raise RuntimeError(
E   RuntimeError: The starlette.testclient module requires the httpx package to be installed.
E   You can install this with:
E       $ pip install httpx

Do you see anything similar when you run tox?