chore: release 0.5.0

[henryiii]

🤖 AI text below 🤖

Bumps the version to 0.5.0 and promotes the package from Alpha to Beta (Development Status :: 4 - Beta).

---

Changelog:

Version 0.5.0

Feature release adding four new bundled plugins and the backend collection loops.

✨ Features

• ast plugin (feat: add ast plugin to read a global literal from a Python file #81) — read a module-level global by name from a Python file via ast.literal_eval, without importing it. Values keep their Python shape, so list/table fields can be filled directly (not just strings).
• pin_installed plugin (feat: add pin_installed plugin for build-time version pinning #80) — pin dependencies to build-environment versions using templates like "torch==x.x.*" (x = installed release component, x+N, trailing *). Implements dynamic_wheel (dependencies are Dynamic in the SDist) and get_requires_for_dynamic_metadata (the bare package names).
• from_file plugin (feat: add from_file plugin for filling fields from files #82) — fill a field from a file: stripped contents for a string field, requirements.txt-style lines for a list field, or a dotted key (optional-dependencies.test) for a table field, one entry per key. pip option lines (-r, …) are a hard error.
• Backend collection loops in the loader (feat: provide the backend collection loops in the loader #78) — loader.py now provides get_requires_for_dynamic_metadata(entries) and dynamic_wheel_fields(entries), so backends get the METADATA 2.2 dynamic set and extra build requirements from one place. Both load providers fresh, keeping dynamic_wheel stateless.

📚 Docs

• Add a scikit-build-core migration guide (docs: add scikit-build-core migration guide #79).

Full Changelog: v0.4.0...v0.5.0