Bump JWT to v1.87.0 to add support for the Cognito Token schema.

[Duslerke]

What:

• Update the Hackney.Core.JWT package multiple versions up (1.49 -> 1.64 -> 1.65 -> 1.66 -> 1.72 -> 1.84 -> 1.87).

Why:

• To get the latest version of the ITokenFactory implementation that adds support for the Cognito token schema.

Notes:

• This seems like a big jump, but it's not as bad as it seems. Due to poor releases labelling, it's extremely difficult to tell what version introduces what changes. However! I've pulled down the 1.49 version of the JWT package and inspected its classes, interfaces, and implementations via ICSharpCode.Decompiler. It would seem that the only notable difference (except for my 1.87 release linked below) is a change of Nbf, Exp, Iat Token class fields data types from int to long (see code). This won't cause any backwards compatibility issues within any of the APIs because 1) they never check those fields, and 2) it's a transition to double length, so the numbers being parsed get more breathing room, not less.
• What changes does latest JWT intoduce? See PR: Add cognito authentication flow token schema support. lbh-core#68.