feat: add support for bun

[danielroe]

🔗 Linked issue

resolves #86

❓ Type of change

• 📖 Documentation (updates to the documentation, readme, or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

This adds support for the bun package manager.

As Bun isn't yet corepack-supported (we can track in oven-sh/bun#4056) this directly runs the bun command.

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[codecov]

Codecov Report

Merging #87 (f15eade) into main (69003dc) will increase coverage by 0.05%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #87      +/-   ##
==========================================
+ Coverage   98.02%   98.07%   +0.05%     
==========================================
  Files           5        5              
  Lines         405      416      +11     
  Branches       64       67       +3     
==========================================
+ Hits          397      408      +11     
  Misses          8        8              

Files Changed	Coverage Δ
src/_utils.ts	98.49% <100.00%> (+0.07%)	⬆️
src/package-manager.ts	100.00% <100.00%> (ø)
src/types.ts	100.00% <100.00%> (ø)