Format the plugin via Spotless

[janfaracik]

Small one to format the project via Spotless.

[duemir]

It's really formatting, not linting, as far as I understand. That's semantics, though.
Is this the same formatting that Core uses and recommends for plugins?
Changing lineEndings is not recommended if I am reading https://github.com/diffplug/spotless/tree/main/plugin-gradle#line-endings-and-encodings-invisible-stuff correctly.

[timja]

It's really formatting, not linting, as far as I understand. That's semantics, though. Is this the same formatting that Core uses and recommends for plugins? Changing lineEndings is not recommended if I am reading diffplug/spotless@main/plugin-gradle#line-endings-and-encodings-invisible-stuff correctly.

Core doesn't have much enabled but this is a subset of what plugins have enabled:
https://github.com/jenkinsci/plugin-pom/blob/master/pom.xml#L648-L657