Add Ubuntu pytest matrix and dedicated coverage CI job with pytest-cov

[Copilot]

CI runs pytest without any coverage tooling — no coverage data is collected. This updates the workflow to add a separate Ubuntu-only pytest matrix for supported Python versions and a dedicated coverage job on Linux x86_64 that produces terminal and XML output, while keeping the existing build/compatibility matrix in place.

Changes

pyproject.toml

• Adds pytest-cov>=5,<7 to the [project.optional-dependencies].test group

.github/workflows/CI.yml

• Adds a new Ubuntu-only pytest job with a Python matrix covering 3.10, 3.11, 3.12, 3.13, and 3.14
• Adds a coverage job (Ubuntu x86_64, Python 3.12) that:
  • Builds and installs the compiled extension + test extras in one step via maturin develop --release --extras test
  • Runs pytest --cov=e57 --cov-report=term-missing --cov-report=xml
  • Uploads coverage.xml as a workflow artifact
• Keeps the existing linux / musllinux / windows / macos matrix jobs intact for build/compatibility coverage
• Updates GitHub Actions in the workflow to current released versions
• Does not introduce any third-party coverage service (e.g. Codecov)

[dancergraham]

@copilot update the coverage step first add a pytest matrix of all currently supported python versions - 3.10 to 3.14 on ubunto only, update the coverage step to use py 3.12, update the github actions to the latest versions

[Copilot]

@copilot update the coverage step first add a pytest matrix of all currently supported python versions - 3.10 to 3.14 on ubunto only, update the coverage step to use py 3.12, update the github...

Addressed in 3b0df4d.

• added a separate Ubuntu-only pytest matrix for Python 3.10 through 3.14
• kept the coverage job on Python 3.12
• updated the workflow action versions across the file