Allow the version token to be a link

Hello,
In my project instead of using a simple `[1.0.0] - 2021-04-06` we use `[1.0.0](#100---2021-04-06) - 2021-04-06` (to quickly focus on the paragraph version and to be more pretty).
But because you only check for `"] - "` to end the parsing of the version then in my changelogs the changelogCheck is going to always throw the error below:

https://github.com/diffplug/spotless-changelog/blob/3b773c36024815f8dc4c07e753dee8ba482f6a51/spotless-changelog-lib/src/main/java/com/diffplug/spotless/changelog/Changelog.java#L252-L257

What do you think?