feat: implement dynamic versioning with setuptools_scm

[nicogodet]

• Replace hardcoded version with setuptools_scm integration
• Configure setuptools_scm to write version to _version.py
• Add fallback mechanisms for development environments
• Update .gitignore to exclude generated _version.py

This change enables automatic version management from git tags, eliminating the need to manually update version strings.

[codecov[bot]]

Codecov Report

:x: Patch coverage is 45.45455% with 6 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
qgis_deployment_toolbelt/__about__.py	25.00%	6 Missing :warning:

@@            Coverage Diff             @@
##             main     #671      +/-   ##
==========================================
- Coverage   71.90%   71.88%   -0.03%     
==========================================
  Files          48       48              
  Lines        3271     3279       +8     
  Branches      576      577       +1     
==========================================
+ Hits         2352     2357       +5     
- Misses        704      705       +1     
- Partials      215      217       +2     

Flag	Coverage Δ
unittests	71.24% <36.36%> (-0.03%)	:arrow_down:

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
qgis_deployment_toolbelt/commands/upgrade.py	68.81% <100.00%> (+3.98%)	:arrow_up:
qgis_deployment_toolbelt/__about__.py	75.00% <25.00%> (-25.00%)	:arrow_down:

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[sonarqubecloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Guts]

AI generated?

[nicogodet]

for version_info_templater part, yes

[Guts]

@nicogodet I think we should first switch to pyproject in a dedicated PR. Check everything works as previously in packaging and then change the way of versioning.

Still I've already made those moves on other projects and it's the good things to do.

[nicogodet]

You already convert this project to pyproject.toml 🧐

https://github.com/qgis-deployment/qgis-deployment-toolbelt-cli/pull/556

[Guts]

You already convert this project to pyproject.toml 🧐

https://github.com/qgis-deployment/qgis-deployment-toolbelt-cli/pull/556

😂 I sincerely and completely forgot about this one

[nicogodet]

Welcome back!

I will take a second look at it and update this PR.

[Guts]

Thinking on this topic, I had the opportunity to work on a similar move (pyproject and dynamic versioning with scm): https://github.com/geotribu/cli/pull/281. What do you think of this approach?

[nicogodet]

Yes, approach in this PR can be simplified. The logic in builder script can be simplified and I need to remember why I set PYTHONIOENCODING...

[Guts]

I need to remember why I set PYTHONIOENCODING...

This PR looks like a memory hole :scream_cat:

[nicogodet]

Need to be re-thinked...