feat: inform user about cli updates

[Guust-Franssens]

📥 Pull Request

• Resolves [FEATURE] Help me keep my fabric-cli updated #71

✨ Description of new changes

Implements automatic update notifications that inform users when a new version of the Fabric CLI is available on PyPI. The check runs on login (fab auth login) and displays a friendly notification if an update is available.

Changes Made

New Files:

• src/fabric_cli/utils/fab_version_check.py - Core version checking module with PyPI integration
• tests/test_utils/test_fab_version_check.py - 100% coverage on fab_version_check.py

Modified Files:

• src/fabric_cli/core/fab_constant.py - Added constants for update checking configuration
• src/fabric_cli/commands/auth/fab_auth.py - Integrated version check on successful login
• docs/essentials/settings.md - Documented the new check_updates setting

Implementation Details

• Once per session: version check is ran whenever a user logs in using fab auth login
• User Control: Can be disabled via fab config set check_updates false
• Silent Failures: Doesn't interrupt user experience if PyPI is unreachable
• Conservative Version Comparison: Uses tuple-based semantic versioning without external dependencies
• Debug Logging: Integrated with existing fab_logger for troubleshooting

Configuration

New config key check_cli_version_updates (default: true) stored in ~/.config/fab/config.json. This setting enables/disables update notifications.

User Experience

When a user logs in and a new version is available:

$ fab auth login -u "$CLIENT_ID" -p "$CLIENT_SECRET" --tenant "$TENANT_ID"

[notice] A new release of fab is available: 1.1.0 → 1.2.0
[notice] To update, run: pip install --upgrade ms-fabric-cli

[Guust-Franssens]

Thanks for the review @aviatco. Your points are valid and I will keep them in mind in my potential future PRs.

I left some of the remarks open (like proper naming and the class one) as these warrant a second review by you to verify if my changes are meeting your request.

[Guust-Franssens]

@aviatco @ayeshurun in f4b4c4e I made a change to ignore pypi.org in the VCR playback. This was causing issues in the tests/test_commands/test_auth.py.

This passes the tests however now during testing of the fab auth login, actual requests to PyPI are being made. I think it would be cleaner to either:

• Re-record the requests made to include PyPI (preferable by one of you as I don't have the full setup)
• I mock the function making the call to PyPI for all tests to auth login. Here I would just make it the mock return value equal to the current __version__

Could you provide some guidance here?