pull: Add deprecated SPDX identifiers

pull: Add deprecated SPDX identifiers

These identifiers are deprecated, but they haven't yet been dropped
from the SPDX spec.  That means that, although they're not
recommended, they're still valid identifiers to use where you can use
other License List 3.0 identifiers.  Listing them here makes it easy
for folks using the deprecated identifiers to look up the associated
FSF metadata.

An alternative approach would be to stick with only non-deprecated
SPDX identifiers here and have users hit the SPDX API to resolve those
before coming to this API.  But the SPDX API does not currently expose
obsoletedBy migration recommendations [1].

[1]: https://github.com/spdx/LicenseListPublisher/issues/12