CI workflows maintenance

[delatrie]

Context

This PR maintains the CI workflow.

Action version changes

• actions/checkout bumped to v7
• actions/setup-python bumped to v7
• dorny/paths-filter bumped to v4
• toolmantim/release-drafter bumped to v7; the release definition is updated

Workflow triggers

This repository does not pin production dependencies. The upside is that CI workflows install packages like end users, i.e., with the latest supported dependencies, which helps catch incompatibility issues early. The downside is that the testing workflow runs only on PRs, which forces PR authors to deal with incompatibilities unrelated to their work.

The PR updates the list of triggers for the testing workflow. The list includes three triggers:

• pull_request: now the workflow is run on all PRs, not just PRs targeting the main branch.
• schedule: the new trigger that runs the workflow weekly to catch incompatibilities caused by new versions of the dependencies.
• workflow_dispatch: a manual trigger that allows you to run tests manually to check that the packages are compatible with the latest versions of dependencies without having to wait for the schedule trigger to kick in.

Other changes

• limit the test workflow concurrency to a single run per Git ref.
• add Python 3.14 to the test matrix and use it for linting.
• remove Python 3.8 and 3.9 from the test matrix.
• remove the TEST_TMP env variable from the test workflow.
• rename the test workflow