[FR] Support the `license` key table values for as long as they are supported by specification

[befeleme]

What's the problem this feature will solve?

With implementing PEP 639, the date for the removal of the support of the table values has been set to 18 February 2026. Can you consider prolonging the warning for (ideally) as long as the specification allows it?
Reasons:

1. PEP 639 doesn't cover all the project cases. Some projects, especially those which produce different sdists and wheels (e.g. using auditwheel), don't have means to express the differing distribution metadata. This is one prominent of a few valid reasons not to migrate to PEP 639.
2. PEP 639 doesn't state when or if the removal of the table keys will be happening in the form of standard, it leaves it to a potential future PEP. In fact, authors were aware the transition will require a lot of heavy lifting and discussions, as well as follow-up specifications, which can easily extend the process to many years.

With that, I'd like to ask you postpone the removal and allow both declarations through the long transition period.

Describe the solution you'd like

See above

Alternative Solutions

No response

Additional context

No response

Code of Conduct

• I agree to follow the PSF Code of Conduct