Early support for Django 6

[bckohan]

No description provided.

[Copilot]

Pull Request Overview

This PR adds early support for Django 6.0 by bumping the package version to 2.2.5 and updating dependency constraints to include Django 6.x versions.

• Version bump from 2.2.4 to 2.2.5
• Django dependency constraint updated from <6.0 to <6.1 to include Django 6.0
• CI/CD pipeline updated to test against Django 6.0a1 prerelease

Reviewed Changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/django_enum/init.py	Updates package version to 2.2.5
pyproject.toml	Updates Django dependency constraint and adds Django 6.0 classifier
doc/source/changelog.rst	Adds changelog entry for v2.2.5 with Django 6.0 support
.github/workflows/test.yml	Adds Django 6.0a1 to test matrix and improves CI configuration
.github/workflows/lint.yml	Restricts workflow triggers to main branch only

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Files with missing lines	Coverage Δ
src/django_enum/__init__.py	100.00% <100.00%> (ø)

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