Fix swift build by adding missing import and updating package.swift #no-public-changes

[phimage]

opening with Xcode the Package.swift file or by using command line

sdk=`xcrun -sdk iphonesimulator -show-sdk-path`
sdkVersion=`echo $sdk | sed -E 's/.*iPhoneSimulator(.*)\.sdk/\1/'`
swift build  -Xswiftc "-sdk" -Xswiftc "$sdk" -Xswiftc "-target" -Xswiftc "x86_64-apple-ios$sdkVersion-simulator"

In fact swift build do not allow missing import

I think new release must be done with that, a 6.0.1 or 6.1.0

--

Also I have added a test with github workflow, but to be activated on IBAnimatable organisation

• an admin must active it here https://github.com/features/actions

[IBAnimatableBot]

	2 Warnings
⚠️	Consider adding supporting documentation to this change. Documentation can be found in the docs directory.
⚠️	Consider adding / updating the demo app.

Generated by 🚫 Danger

[tbaranes]

Thanks for this fix, I enabled GitHub Actions as you asked :)

[tbaranes]

Why importing it here instead at the top of the file with the other import?

[phimage]

I am thinking for later, moving the import and the code to its own file

And I see better fix, I will update, move it to CALayerExtension now
and move import at top for CGFloat