semver: Update FAQ entry on regular expressions

[har7an]

with a third variant that works without non-capturing groups and is compatible with POSIX regex (i.e. for use in bash). This originates from an issue I opened earlier, found here: #981

There is a small repo which contains the terse form of the regex along with a more human-readable one and a bash script that demonstrates and runs the regex against the set of test strings from regex101. I also went and created a snippet for this regex on regex101.

I only just noticed that there is a long-standing open PR which adds exactly the same regex (but with less explanation) to the FAQ.

[jwdonahue]

I only just noticed that there is a #724 which adds exactly the same regex (but with less explanation) to the FAQ.

Doh! I forgot all about that, sorry.

[har7an]

@jwdonahue Any news on this?

[jwdonahue]

@har7an

I think we're waiting on the maintainers.