Update macCatalyst deployment target to v15

Avoid compile error.
❯ xcrun xcodebuild build \
  -scheme "CallableKitURLSessionStub" \
  -destination 'platform=macOS,variant=Mac Catalyst'
error: The package product 'CallableKitMacros' requires minimum platform version 15.0 for the Mac Catalyst platform, but this target supports 13.1 (in target 'CallableKitURLSessionStub' from project 'CallableKit')
error: The package product 'CallableKitMacros' requires minimum platform version 15.0 for the Mac Catalyst platform, but this target supports 13.1 (in target 'CallableKit' from project 'CallableKit')

Merge pull request #43 from sidepelican/fix_platformversion

Lower platform version causes other xcodebuild issues

Merge pull request #42 from sidepelican/minios

Set min platform versions

Merge pull request #40 from sidepelican/split_package

Split targets into multiple packages

Merge pull request #32 from sidepelican/transferringRawValue

Add @CallableKit marker comment option

Merge pull request #31 from sidepelican/outername

Add missing support for argument outer name

Update C2TS

Add explicit @sendable

Merge pull request #30 from sidepelican/hummingbird

Add Hummingbird support