Do not use 0 to indicate the latest ruby version to parse

[Earlopain]

This makes it hard to do version checks against this value. The current version checks work because there are so few possible values, and they are exclusively !=/==` checks.

As an example, #3337 introduces new syntax for ruby 3.5 and uses PM_OPTIONS_VERSION_LATEST as its version guard. Because what is considered the latest changes every year, it must later be changed to parser->version == parser->version == PM_OPTIONS_VERSION_CRUBY_3_5 || parser->version == PM_OPTIONS_VERSION_LATEST, with one extra version each year.

With this change, the PR can instead write parser->version >= PM_OPTIONS_VERSION_CRUBY_3_5 which is self-explanatory and works for future versions.

[eregon]

Looks great to me, I have noticed this as well as being rather brittle but didn't get around fixing it myself, thanks!

[eregon]

Could be:

Suggested change

	LATEST(V3_5.value);
	LATEST(0);

So that there is no risk to forget updating it.
And then 0 would be translated when "parsing" the options (already done in pm_parser_init but not sure if that gets called when using the serialization).
Same for javascript/src/parsePrism.js below

[Earlopain]

I agree that it is nicer that way. It works because pm_options_read (which does the deserialization is always followed by pm_parser_init. I only tested ffi though but they should all go through the same thing in the end.

[eregon]

This looks ready to merge for me, except maybe the PR title could be clearer like:

Use comparison operators for parse versions checks instead of ==/!=
or
Make parse version values monotonic to clarify version checks

@tenderlove or @Morriar Could you do a second review and merge?