fix: fallback to local package manager when corepack not installed

[pi0]

🔗 Linked issue

resolves #8
resolves #9

❓ 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

Resolves issues with envs that have no local version of corepack available.

📝 Checklist

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

[codecov]

Codecov Report

Merging #94 (2c3b85f) into main (c32c998) will decrease coverage by 0.31%.
The diff coverage is 92.59%.

@@            Coverage Diff             @@
##             main      #94      +/-   ##
==========================================
- Coverage   96.63%   96.33%   -0.31%     
==========================================
  Files           5        5              
  Lines         416      436      +20     
  Branches       60       67       +7     
==========================================
+ Hits          402      420      +18     
- Misses         14       16       +2     

Files Changed	Coverage Δ
src/_utils.ts	94.15% <92.59%> (-0.63%)	⬇️