Make PyJWT an optional dependency

[akx]

Pull Request check-list

Please make sure to review and check all of these items:

• Do tests and lints pass with this change?
• Do the CI tests pass with this change (enable it first in your forked repo and wait for the github action build to finish)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?
• Is there an example added to the examples folder (if applicable)?
• Was the change added to CHANGES file?

NOTE: these things are not required to open a PR and can be done
afterwards / while the PR is open.

Description of change

For users who do not need JWT auth, pulling in PyJWT and its transient dependencies is unnecessary.

This makes the JWT dependency optional. Follows up on #3462.

[petyaslavova]

Hi @akx thank you for your contribution! We’ll review your change soon.

[petyaslavova]

LGTM.

[petyaslavova]

@akx I forgot to request one more change... Currently in the actions.yml the optional dependency is added for installation and the tests are executing without issues, but the information about the change is not added to the CONTRIBUTING.md guide. Could you please update the instructions there as well?

[akx]

@petyaslavova Done. That file doesn't note the hiredis or ocsp extras though either, but at least it now notes jwt.