Kotlinx.serialization: Improve name of gradle plugin

[hastebrot]

I think the name of the gradle plugin should be changed to have a -gradle-plugin suffix like other gradle plugins:

• before: kotlinx-gradle-serialization-plugin
• after: kotlinx-serialization-gradle-plugin

~gradle
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$compilerVersion"
classpath "org.jetbrains.kotlin:kotlin-native-gradle-plugin:${property('konan.version')}"
classpath "org.jetbrains.kotlin:kotlinx-gradle-serialization-plugin:$serializationPluginVersion"
~

[sandwwraith]

There is another option of naming, to be consistent with the rest of Kotlin compiler plugins: just kotlinx-serialization. (https://kotlinlang.org/docs/reference/compiler-plugins.html).

[sandwwraith]

So it's renamed to kotlin-serialization now.