[Issue #77] Clean up platform specific logic and remove unnecessary f…

[LowAmmo]

…iles

• Modify all of the os() compiler directives to just make an exception for linux, but group other platforms together

  • Will make supporting iPadOS & VisionOS easier in the future

• Specify platform versions in Package.swift to match those in cocoapods

Description

Extracted some of the changes from #78 that are just around cleaning up the compiler directives around Linux vs Apple platforms.
Also cleaned up any around Swift version being >=5, and instead have the dependency managers (cocoapods or SPM) enforce already being on Swift 5+.

No logic changes - only restructured the "#if" logic to be a little cleaner, and should be able to easily support VisionOS, iPadOs, or other future Apple platforms without a code change - just a Package.swift or podspec change.

After Merging

After merging this in, could consider creating a new tag - 2.0.3.

Motivation and Context

This is Part 1 of resolving Issue #77

Trying to separate out the changes to make them easier to review. (from the discussion on the Pull Request #78 )

How Has This Been Tested?

Tested locally via unit testing and in our app that consumes this via SwiftJWT.

Checklist:

• I have submitted a CLA form
• If applicable, I have updated the documentation accordingly.
• If applicable, I have added tests to cover my changes.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[LowAmmo]

@dannys42 - Here are JUST changes to clean up the compiler directives. So it looks like a lot of changes - but really it's all just swapping the order of the directive so instead of:

 #if os(macOS) || os(iOS) || os(tvOS) || os(watchOS)
     // Apple Platforms Logic
 #elif os(Linux)
     // Linux/OpenSSL Logic
 #endif

I set everything up like this:

 #if os(Linux)
     // Linux/OpenSSL Logic
 #else
     // Apple Platforms Logic
 #endif

Also...looks like this repo is a mix of using spaces and tabs... If you want me to make everything tabs I can (or could also do a separate commit for that), just let me know.

[LowAmmo]

@dannys42 - Just a ping to hopefully get this on your radar sometime soon...

[LowAmmo]

@dannys42 - Just a ping to see about getting this PR pulled in...