Enable support for intelliJ placeholder for year in license header

[sameer-b]

Change log

• Enable support for IntelliJ style year tokens of the format $year.today
• I raised an issue earlier Enable support for IntelliJ compatible place holders in license header templates #541

[nedtwigg]

Thanks, looks very good. I made some minor tweaks to the docs and implementation. If you update the changelogs (root, plugin-gradle, and plugin-maven are all affected, and can have the same changelog entry if you want), then I'll merge and release.

[sameer-b]

@nedtwigg Done! Could you take a look?

[nedtwigg]

For future reference, there are three different changelogs (as documented in the PR template) - one for Spotless developers, one for the gradle plugin, and another for the maven plugin. I made a minor edit to your entry and copied it to the other affected changelogs.

Thanks for the contribution!

[nedtwigg]

Released in x.28.0

[nedtwigg]

If you care about license headers, you should checkout ratchetFrom 'origin/master'.