Change iOS deployment target for Xcode 12

[davbeck]

This removes the warning about iOS 8 no longer being supported in Xcode 12 while maintaining support for older versions of Xcode. Technically checking the compiler version isn’t an exact 1:1 for checking for Xcode version, but in practice should work in all scenarios.

[JackoPlane]

@davbeck Could we get this merged? Would a great help to not have Xcode complain about deployment target when using the SPM module

[ghost]

@julienbodet Any chance that this could get released as a patch? The warnings have been there for quite some time now 😬

[JackoPlane]

@WilliamDenniss Could we get this merged some time soon?

[ChrisPearce]

Is there any update of whether this PR will be merged?

Our CI build processes continue to show these warnings when using this library

[robinhayward]

+1 for a merge please, can't find any other way to remove these warnings. (SPM)

[moban-michael]

Like to see it merged asap to get rid of warnings with SPM

[jakobmygind]

Please merge this

[CemYil03]

Is also covered in #661. Can anyone contact the maintainers to merge one of those? These warnings are really annoying to me...

[Oliver-Binns]

#661 is a better implementation of this. It would be preferable to merge that instead.

The platform declarations can be removed entirely as they match the minimum version supported by SPM: https://forums.swift.org/t/xcode12-minimum-deployment-target-and-spm/40467 https://github.com/nanopb/nanopb/pull/585/files