Add missing SPDX ID and OSI name

[perillo]

Some licenses are missing the SPDX ID, thus making the actual license uncertain.

As an example, in https://pypi.org/project/undatum/ the license is "OSI Approved :: BSD License" but pypi reports "BSD License (MIT)".
The actual license file reports MIT, so this is certain an issued caused by the author.

I suggest to add at least the OSI license name and SPDX ID for the popular/strong community licenses: https://opensource.org/licenses/?categories=popular-strong-community.

Thanks.

See also #70

[di]

The reason the undatum license is rendered like that is because they set both the License: MIT metadata field and the OSI Approved :: BSD License classifier. PyPI is making a best effort to display both things the user has provided.

I think we can probably close this as a duplicate of #17 because it covers updating the license classifiers to make them more accurate.

[perillo]

@di I agree. Thanks and sorry for not having noted #17.