Whitelist for spec-name changes

[ggwpez]

Sometimes we want to do a spec name change. Then there could be an arg to allow the spec-name check to know about this.
Eg: --known-good-spec-name-changes="1_000_000/old_name:2_000_000/new_name" or something like this.

Its a very niche case, so probably low prio. But could be a good issue for newcomers.

[liamaharon]

There is already a --disable-spec-name-check arg. So this is low priority I think.