Update from 3.2.1 to 4.0.0.

<ChangeLog>

4.0.0 > 2021-02-16

New features

• [BREAKING] Remove the prn option as it's not included in the spec any longer #114
• [BREAKING] Avoid adding an exp claim automatically. Instead, the --exp flag must be present, with or without a value
• Support adding jti when encoding
• Add no-iat flag to disable automatic iat claim generation
• Add an --iso8601 flag to represent date-based claims as ISO 8601 date strings. Only applies to iat, exp, and nbf

Bug fixes

• Trim whitespace around a jwt before encoding #120

3.3.0 > 2020-12-24

New features

• Default decoding to JSON when not in a TTY #100

</ChangeLog>