fix: allow object for overriding private key when signing

[39hn-zz]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior?

Issue Number: N/A

It must be able to pass an object { key, passphrase } as privateKey for RSA and ECDSA algorithm.
It's possible on module option but not on overriding private key when signing.

What is the new behavior?

Fix privateKey type to allow to pass object for overriding private key when signing

Does this PR introduce a breaking change?

• Yes
• No

Other information

[micalevisk]

could you please change the line below from npm@latest to npm@^8 to fix the pipeline

jwt/.circleci/config.yml

Line 25 in ef435fb

command: npm install -g npm@latest

[39hn-zz]

could you please change the line below from npm@latest to npm@^8 to fix the pipeline

jwt/.circleci/config.yml

Line 25 in ef435fb

command: npm install -g npm@latest

sure!!

[david-a]

Hi, I haven't noticed your PR and opened a similar one, but with tests and no other changes (e.g. config.yml)
#1192

[kamilmysliwiec]

lgtm