Add 'may-spotless-apply' profile

[Vlatombe]

I often find myself forgetting to apply spotless before committing.

On some repositories, I have set up a pre-commit git hook running mvn spotless:check. However, this has to be set up on each repository that has spotless check enabled, and disabled on those which don't.

I think this goes one step further, by defining a conventional maven profile may-spotless-apply that will run spotless:apply only if spotless is enabled for the given repository.

This allows any user to incorporate -Pmay-spotless-apply as part of their usual build command (or defined in their maven settings active profiles section), and have spotless:apply automatically called if the project has it enabled.

Example Maven settings.xml

<settings>
  [...]
  <activeProfiles>
    [...]
    <activeProfile>may-spotless-apply</activeProfile>
  </activeProfiles>
</settings>

See also jenkinsci/pom#611

Testing done

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[jglick]

defined in their maven settings active profiles section

What would this look like? If you just set

        <profile>
            <id>may-spotless-apply</id>
            <activation>
                <activeByDefault>true</activeByDefault>
            </activation>
        </profile>

(with no further configuration in ~/.m2/settings.xml) does that in fact cause the config in this parent POM to be run?

[jglick]

plugin-pom/pom.xml

Lines 126 to 127 in 64885a6

	<!-- Set to false to enable Spotless -->
	<spotless.check.skip>true</spotless.check.skip>

FTR

[Vlatombe]

In fact, Maven settings.xml has a specific section for profiles you want to activate unconditionally.

<settings>
  [...]
  <activeProfiles>
    [...]
    <activeProfile>may-spotless-apply</activeProfile>
  </activeProfiles>
</settings>

[jglick]

Worth mentioning in https://github.com/jenkinsci/plugin-pom/blob/master/README.md#formatting I guess.

[timja]

Can you document it please

[basil]

Thanks for the PR!