Update to JWTKit 5

[0xTim]

Update library to use the new JWTKit 5

Builds on top of #13 so that should be merged first

[0xTim]

cc @ptoffy

[alexanderjordanbaker]

@0xTim Are you still planning to move this PR from Draft -> Ready?

[0xTim]

@alexanderjordanbaker yes we will do once we have a release of the new version of JWTKit with a stable API

[0xTim]

@alexanderjordanbaker this is pretty much ready. I don't know whether you want to wait until JWTKit v5 is out of Beta or you're happy to take it as is. We're not anticipating any API changes

[0xTim]

@ptoffy FYI some conflicts here (also we should have a discussion about the Sendable stuff)

[alexanderjordanbaker]

@0xTim We would prefer to wait until the underlying software is out of beta before merging

[0xTim]

@alexanderjordanbaker yep fully agree, we're planning on tagging a stable release pretty soon

@ptoffy want to tag an RC of JWTKit and fix the conflicts?

[ptoffy]

@0xTim done

[ptoffy]

JWTKit 5 is out so this should be ready cc @0xTim

[0xTim]

@ptoffy can we bump this to Swift 6?

[0xTim]

@alexanderjordanbaker this should be ready to go now

[PWrzesinski]

Hello @alexanderjordanbaker, could this one be prioritized? Currently encountering an issue with JWTKit 4 and this is blocking me from upgrading. Thanks!