Added support for generic NativeCmd step

[tisoft]

Allows to call locally installed binaries to format files

[tisoft]

Would like to use this, to call a custom formatter, that is installed locally, but can't be added as a "real" formatter into spotless.

TODO: Support writing the unformatted string to a temp file and read it back from another (or the same) file

[nedtwigg]

Cool feature, needs docs and changelog entries (root and plugin-maven).

[nedtwigg]

TODO: Support writing the unformatted string to a temp file and read it back from another (or the same) file

This feature is best left unimplemented, imo. stdin/stdout are perfectly suited for this purpose. Unless you absolutely, unavoidably need filebased-IO for a usecase you have right now, I think we're better off leaving this out. 100% guarantee people waste hours fiddling with the filename, whether its local or relative, tools that don't flush filesystem cache, etc, not to mention performance.

[tisoft]

• Added CHANGES.md entries
• Added doc in README.md
• Incorporated review comments

[nedtwigg]

Please merge the latest origin/main into this PR. That should fix CI, at which point I can merge and release.

[tisoft]

@nedtwigg rebased against main and fixed one copyright date. The test failure seems unrelated to me.

[nedtwigg]

Agree re: test faillure. I would merge if there wasn't low-hanging fruit re: the absolute path.

[nedtwigg]

Published in plugin-maven 2.14.0.