RFC: IR format versioning

[iamdanfox]

Rendered

Before this PR

We're somewhat blocked on all the issues tagged 'IR change' and also #227 because the mechanism for actually making an IR change is undefined.

After this PR

==COMMIT_MSG== RFC: IR format versioning recommends single-digit scheme ==COMMIT_MSG==

This RFC just tackles the first problem for an IR rev - will follow up with a separate RFC to discuss lossless upgrading/downgrading etc.

Possible downsides?

A bad decision about IR versioning could result in the conjure ecosystem becoming confusing to use / contribute to, or alternatively introduce excessive overhead and unintentionally hamper development.

The upside is that this RFC can always be superseded if significant problems arise.

[carterkozak]

This looks sane to me. It reinforces the decision to support a single integer version field, and I don't see serious downsides. If we were to fundamentally change the meaning of the IR we could also rename the version, causing all existing non-compliant parsers/generators to fail as we would expect in alternative version proposals.

[stale[bot]]

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