Versioning of new specs based on the Jelly serialization format

[Ostrzyciel]

In #11 we are working on a new format for RDF Patch. This is not a direct extension of the Jelly serialization format, but it does use some protos from that.

There may be more such formats building on top of the core format in the future. The question is how should we version them.

I still have to think this through, but here some notes on how it may work. Here "Jelly-RDF" stands for the Jelly serialization format. "Jelly-X" is a hypothetical new format building on top of it (like Jelly-Patch).

• Jelly-RDF MINOR bump -> Jelly-X MINOR bump
  • What happens if the Jelly-RDF change is irrelevant to Jelly-X? For example, it's just a change in the metadata. Then the bump makes no sense.
• Jelly-X MINOR bump -> nothing
  • Which means that Jelly-RDF and Jelly-X should not be tied 1:1

...thinking required.