Add return type parameters to JwtBearer class

[rserry]

The return types handle this deprecation warning with relation to the League\OAuth2 bundle:

Method "League\OAuth2\Client\Grant\AbstractGrant::getName()" might add "string" as a native return type declaration in the future. Do the same in child class "TheNetworg\OAuth2\Client\Grant\JwtBearer" now to avoid errors or add an explicit @return annotation to suppress this message.

Method "League\OAuth2\Client\Grant\AbstractGrant::getRequiredRequestParameters()" might add "array" as a native return type declaration in the future. Do the same in child class "TheNetworg\OAuth2\Client\Grant\JwtBearer" now to avoid errors or add an explicit @return annotation to suppress this message.

[hajekj]

Thanks for the contribution!

[rserry]

@hajekj Thanks for merging!
How often do you do new releases? Just want to know when I can get these changes in my project to remove the warnings 😁

[rserry]

@hajekj can you create a new release?

[hajekj]

Done - https://github.com/TheNetworg/oauth2-azure/releases/tag/v2.2.4