Build: Fix artifacts signing for maven central

With gradle > 5.0 `publish()` helper call should be done before
`noDefaultJar()` or any other artifact hacks, otherwise singing plugin doesn't sign any jars

libraries/tools/kotlin-gradle-plugin/build.gradle.kts

@@ -11,13 +11,14 @@ plugins {
     id("jps-compatible")
 }
 
+publish()
+
 // todo: make lazy
 val jar: Jar by tasks
 runtimeJar(rewriteDepsToShadedCompiler(jar))
 
 sourcesJar()
 javadocJar()
-publish()
 
 repositories {
     google()