Release to Maven Central

[dzikoysk]

Hey, currently, this plugin is only released to Reposilite:

• https://maven.reposilite.com/#/releases/io/javalin/community/graphql/javalin-graphql

So it might be a good idea to push this to the community group with other plugins:

• https://repo1.maven.org/maven2/io/javalin/community/

And then release only snapshot builds (per commit) to Reposilite's snapshot repository. Also, it might be a good idea to bump other dependencies & release it as 5.6.3, so it'll catch up with one of the last releases of Javalin's 5.x branch.

If you have some issues with Gradle/etc., feel free to ask :)