Improve regex

[cj81499]

Notable changes to this regex:

• "v" is not included in match[1]. This is to maintain consistency across the output string[]
• regex captures pre-release versions.

[cj81499]

It just occurred to me that there might be an official regex. There is: https://semver.org/#is-there-a-suggested-regular-expression-regex-to-check-a-semver-string.

Should we be using it?