Implement list users limit

[adamjcampbell]

Awesome work on the SDK 😄 Found a missing feature so I thought I'd implement it

Changes

This PR adds the ability to limit the number of resources (users) returned from the list users endpoint

Notes

I wasn't sure how to test the project how it is currently set up but was to enable the use of swift test by adding the following test target

        .testTarget(
            name: "AppStoreConnect-Swift-SDK-Tests",
            dependencies: ["AppStoreConnect-Swift-SDK"],
            path: "Tests",
            exclude: ["LinuxMain.swift"]
        )

[SwiftLeeBot]

	Messages
:book:	View more details on Bitrise
:book:	AppStoreConnect-Swift-SDK: Executed 149 tests, with 0 failures (0 unexpected) in 0.631 (1.437) seconds

AppStoreConnect_Swift_SDK.framework: Coverage: 81.64

File	Coverage
ListUsers.swift	100.0%	✅

Generated by :no_entry_sign: Danger Swift against 1a2807da1c1d4863da3adce0f4593ad128233e8a

[adamjcampbell]

@AvdLee would having that test target added to Package.swift in another PR be helpful?

Or is there another way to run the tests from the command line or Xcode?

[AvdLee]

~@adamjcampbell we have a test target in the Package.swift but it's commented out. If we wouldn't do that, every package fetch would also fetch our test target and its dependencies.~

I now realize we don't have that test target, so yes, please do add it if you will! However, add it with the // dev if possible due to the above reasons.

This is fixed in Swift 5.2 but not yet implemented. Therefore, we still have the // dev in front of each. https://github.com/AvdLee/appstoreconnect-swift-sdk/blob/master/Package.swift#L21

[SwiftLeeBot]

Congratulations! :tada: This was released as part of Release 1.0.2 :rocket: