Consider changes to Unicode-TOU

[swinslow]

This is following from the discussion on the spdx-legal mailing list at https://lists.spdx.org/g/Spdx-legal/topic/97116566

Unicode-TOU is not a versioned identifier. It points to the license text for the Unicode Terms of Use as they existed as of (I believe) 2014. But the terms of use posted on the Unicode website at https://www.unicode.org/copyright.html have evolved over time, and the mailing list thread discusses how this has caused some confusion with folks using Unicode-TOU to refer to the wrong set of terms.

A separate issue #1851 discusses whether to add a new, separate identifier with the current updated terms.

For the current Unicode-TOU identifier, we should consider either or both of the following options:

1. For the license's Full name, modify it to be Unicode Terms of Use - 2014 or something similar, to help emphasize that it is the 2014 version (again, assuming that's the correct year - should be verified); and/or
2. Deprecate Unicode-TOU as an identifier, and add a new ID Unicode-TOU-2014 with the same existing content.

I'm in favor of 1, and on the fence for 2. Interested in other community members' thoughts.

For clarity, in neither case would we remove Unicode-TOU as a valid identifier. It would remain valid (even if deprecated) and pointing to the existing license text that's currently associated with it.