When targeting macOS, v0.19.0 Requires macOS 14

[STREGA]

Due to JavascriptEventLoop changes, projects that target both WASI and macOS now require macOS 14.

This is a problem because Xcode does not respect SPM target conditionals, so JavaScriptKit is always built when a project supports macOS and has JavaScriptKit as a dependency.

Stubs for the JavascriptEventLoop changes will need to be added to allow macOS builds that target ABI earlier then macOS 14.

[STREGA]

This issue was fixed by #232