Improvement: Publish gradle plugin to gradle plugin portal

[robert3005]

Before this PR

After this PR

==COMMIT_MSG==
Publish gradle plugin to gradle plugin portal
==COMMIT_MSG==

Possible downsides?

[iamdanfox]

IIRC the :palantir-java-format-spi was a blocker to successfully publishing to the gradle plugin portal... dan had this originally: #24

[robert3005]

I really care that the gradle plugin markers are published so I could just turn on automatedpublishing and not do the rest

[robert3005]

eh, this should just work as the spi is published as a library

[iamdanfox]

Actually I think the problem before was that using the plugins {} syntax had a hard-coded list of repositories that it would try to load jars from, and our old bintray thing was obviously not one of them... given that we're now publishing to MavenCentral, maybe this is no longer a problem??

Think this is worth a shot, but will defer the final +1 to a current infra team member.

[robert3005]

you can always add a repo under pluginManagement in settings.gradle

[carterkozak]

lgtm

[svc-autorelease]

Released 2.24.0