fix(shorebird_cli): use completion command when compiling shorebird for Windows

[bryanoltman]

Description

Fixes the issue where attempting to compile shorebird for windows results in the following:

Running pub upgrade... 
PathNotFoundException: Cannot open file, path = 'D:\a\shorebird\shorebird\packages\bin\internal\flutter.version' (OS Error: The system cannot find the path specified.
, errno = 3)
bin/cache/shorebird.snapshot: Error: Error when reading 'bin/cache/shorebird.snapshot': The system cannot find the file specified.

Type of Change

• ✨ New feature (non-breaking change which adds functionality)
• 🛠️ Bug fix (non-breaking change which fixes an issue)
• ❌ Breaking change (fix or feature that would cause existing functionality to change)
• 🧹 Code refactor
• ✅ Build configuration change
• 📝 Documentation
• 🗑️ Chore