Cleanup and repair repo for 2023

[BritneyS]

This is currently a work in progress to address tech debt and update the project.

[BritneyS]

Just added some notes about some non-obvious things I did to cleanup the repo. Most were around addressed warnings specifically from XCode, and changing Build Settings were done through the GUI in XCode.

[BritneyS]

This was replaced since operatingSystemName() is now deprecated, and Apple recommends using -operatingSystemVersionString instead. But this also means that both fields name and version have the same value, so this might need addressing later on.

Src: https://developer.apple.com/documentation/foundation/processinfo/1407388-operatingsystemname

[BritneyS]

Committing this to the repo was recommended by Apple.

Src: https://stackoverflow.com/questions/53034303/should-xcshareddata-be-checked-into-git-repo-for-xcode-project

[BritneyS]

Deleting outdated framework search paths was recommended as a fix for the ld: warning: directory not found for option '-F... warning.

Src: https://stackoverflow.com/questions/9458739/ld-warning-directory-not-found-for-option

[BritneyS]

Removed this non-Swift file from the list of Compile Sources to fix the no rule to process file... warning for this file.

Src: https://stackoverflow.com/questions/22778021/xcode-warning-no-rule-to-process-file-when-build-phases-has-this-file

[BritneyS]

Wanted to note that I suspect that the Apple Pay integration tests fail because of outdated Apple Pay payment method data, where the year is behind, since the response from Spreedly is:

{"errors":[{"attribute":"year","key":"errors.invalid","message":"Year is invalid"}]}

This causes the Optional transaction.applePay to be nil when forcibly unwrapped by the ! "bang" operator. In Swift, Optionals are values that aren't guaranteed to be truth-y, so are usually unwrapped with ? operators. I think using ! in tests where you want failures to reveal themselves is fine, though. But in the SDK, maybe the exception for a bad payment method should be caught sooner, before using it as an Apply Pay PM.