[4.9] Default openapi version in Context to 3.0.0

[DerManoMann]

Fixes #1562

This PR also (re-)enables the deprecation trigger in Context:detect(). The problems the changes around the version check illustrate how fragile the whole concept of Context is and not caring about where/what is in the context is asking for trouble.

[gnutix]

I'm not sure I understand how the bug happens and why this PR would fix it. From my POV, it seems like you had some logic inlined in a method, and now you've reverted that inlinment. But I don't see a "change" in the logic / flow of code itself. Could you explain it to me? I'm puzzled.

[DerManoMann]

I'm not sure I understand how the bug happens and why this PR would fix it. From my POV, it seems like you had some logic inlined in a method, and now you've reverted that inlinment. But I don't see a "change" in the logic / flow of code itself. Could you explain it to me? I'm puzzled.

The difference with using isVersion is that there is a check if version is checked at all. Comparing context->version directly does not have that check and doesn't care if the version is set at all.

I've removed the check and context will now default to 3.0.0 if no version is set. This is still not ideal IMO, but a safer version of how it was before.

Since the syncing of the 'final' value of the version string happens in Generator::generate, when creating Context instances outside the default flow it might be good to set the expected version on the context (just like any other context property) provided the target version is known/available at the time.