Mark plugin @threadSafe to comply with Maven 3.5.0 parallel execution

[EHJ-52n]

When executing a parallel build with a whitespace-maven-plugin execution, Maven 3.5.0 will output a warning

[WARNING] *****************************************************************
[WARNING] * Your build is requesting parallel execution, but project      *
[WARNING] * contains the following plugin(s) that have goals not marked   *
[WARNING] * as @threadSafe to support parallel building.                  *
[WARNING] * While this /may/ work fine, please look for plugin updates    *
[WARNING] * and/or request plugins be made thread-safe.                   *
[WARNING] * If reporting an issue, report it against the plugin in        *
[WARNING] * question, not against maven-core                              *
[WARNING] *****************************************************************
[WARNING] The following plugins are not marked @threadSafe in module:
[WARNING] whitespace-maven-plugin:whitespace-maven-plugin:1.0.4
[WARNING] Enable debug to see more precisely which goals are not marked @threadSafe.
[WARNING] *****************************************************************

Can you add this please? Thank you very much.

[dantwining]

Hi, I will try to look at this. Are you able to help review the code for thread safety? That would help a lot. If you're feeling really keen, then a PR with the annotation in would give you all the kudos :) Also, it would be good to know if you're consuming the plugin via maven central, as I will need to fix the build/publishing as well if that's the case. Thanks.

[EHJ-52n]

Hi @dantwining,
I am using the plugin via maven central. Regarding the contribution, I can promise to test any snapshot version you provide my somehow but I do not have the time for coding or detailed code review.
Kind regards!

[hazendaz]

@EHJ-52n @dantwining This is super easy PR. formatter-maven-pugin already has this so you can see it here. Since this plugin in my opinion is a really small subset of formatting, it is nothing to really test, just add the flag and move on. I can raise a PR. I'm looking to use this anyways for those that are not ready for full formatting as it does a minimum approach which is far less of a concern than full formatting. If this tests out fine for my needs, I'll fork and raise a PR here.

[hazendaz]

@dantwining I'll take care of this one. I used your library on mybatis-3 and it worked really well.

[hazendaz]

This is done on the fork and will be released today https://github.com/hazendaz/whitespace-maven-plugin