Gradle plugin as a fat jar.

Version 2.5.6 exposes the Gradle plugin as a fat jar to workaround a long standing issue where older versions of okio and/or antlr would be loaded first in the classpath and override the versions required by the plugin (See #2287, #2359, #2886, #2939, #3022).

It does so by relocating and packaging the following dependencies inside apollo-gradle-plugin.jar:

• com.benasher44.uuid
• com.squareup.kotlinpoet
• com.squareup.javapoet
• com.squareup.moshi
• okhttp3
• okio
• org.antlr

The only functional change in this version is #3039 to include better exception messages, courtesy of @semaphore3000.

If you notice anything classloading-weird or if this doesn't work in your setup, please open an issue.