Adding Swift-Build

[leogdion]

• Project Name: swift-build
• Project URL: https://github.com/brightdigit/swift-build/actions/runs/17625568733
• Project Description: A comprehensive GitHub Action for building and testing Swift packages across all platforms with intelligent caching and zero-config setup.
• Why it should be added to awesome-swift:
• At least 15 stars (GitHub project)
• Support Swift 5
• Updated contents.json instead of README
• Lib is fully open sourced, written in Swift and not a wrapper over compiled lib
• Description does not say "written in Swift" or variant 🤓

[vpeschenkov]

@leogdion thanks!