ci: bump CI to Python 3.11 and refresh deprecated GitHub Actions

[SarthakB11]

Filing in parallel with the new issue #787. Happy to adjust scope after maintainer review.

Python 3.8 reached EOL on 2024-10-07. actions/checkout@v3, actions/setup-python@v4, and actions/setup-node@v3 still pull the deprecated Node 16 runner that GitHub started flagging across all repos.

Changes:

• .github/workflows/lint-check.yml: actions/checkout@v3 -> @v4, actions/setup-python@v4 -> @v5 with python-version: "3.11", actions/setup-node@v3 -> @v4.
• .github/workflows/integration-tests.yml: actions/checkout@v3 -> @v4.
• src/api-engine/tox.ini: envlist and [gh-actions] map updated from py38 to py311.

3.11 is the safest middle of Django 4.2 LTS's supported range (3.10/3.11/3.12). requirements.txt dependencies (Django 4.2.16, djangorestframework 3.15.2, cryptography 45.0.6) all support 3.11.

pygraphviz==1.5 in requirements is unrelated here; the lint job only installs flake8, not the project, so it does not affect this workflow.

Closes #787.

[Copilot]

Pull request overview

Updates the repository CI configuration to run linting/tox under Python 3.11 and to use current major versions of commonly used GitHub Actions, avoiding deprecated Node 16-based action runtimes.

Changes:

• Bumped actions/checkout to v4 in lint and integration test workflows.
• Bumped actions/setup-python to v5 and updated the lint job to use Python 3.11.
• Updated src/api-engine/tox.ini to run py311 (and map GitHub Actions’ Python 3.11 to py311 via tox-gh-actions).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
.github/workflows/lint-check.yml	Updates checkout/setup actions and moves lint CI to Python 3.11.
.github/workflows/integration-tests.yml	Updates checkout action to the current major version.
src/api-engine/tox.ini	Switches tox envlist and GH Actions mapping from py38 to py311.

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[YoungHypo]

LGTM. One follow-up: the runtime image is still pinned to Python 3.8 in the api-engine Dockerfile. We should upgrade that as well

[SarthakB11]

Done in 5bd34b8, bumped src/api-engine/Dockerfile to python:3.11 to match the workflow. src/agents/hyperledger-fabric/Dockerfile is on python:3.13, which I left alone (different runtime, separate concern); happy to align that in a follow-up if you prefer.

[SarthakB11]

Reverted the Dockerfile bump in f6bfc34. Moving the api-engine runtime to python:3.11 breaks the image build: the pinned psycopg2-binary==2.8.4 and pygraphviz==1.5 do not compile against the 3.11 C API (Py_TYPE is no longer an lvalue, so psycopg2 needs >=2.9; pygraphviz needs a newer release too).

That is a larger dependency-upgrade change than this PR should carry, so I have scoped this PR back to the CI workflow + tox bump (which is what your approval covered). The lint job runs flake8 under 3.11 and does not build the project, so it stays green. Happy to open a separate PR upgrading the api-engine runtime image once the psycopg2/pygraphviz pins are moved forward and tested.

[SarthakB11]

@YoungHypo when you have a moment, this is ready for another look. The Dockerfile bump is reverted (the runtime image needs psycopg2 and pygraphviz pin upgrades before 3.11 can build cleanly, so that's better as a separate PR). The CI workflow + tox bump is what remains. CI runs are pending workflow approval on the revert commit.