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/kotlinx-metadata/jvm/build.gradle.kts

@@ -47,6 +47,11 @@ dependencies {
     testRuntime(project(":kotlin-reflect"))
 }
 
+
+if (deployVersion != null) {
+    publish()
+}
+
 noDefaultJar()
 
 task<ShadowJar>("shadowJar") {
@@ -75,8 +80,3 @@ sourcesJar {
 }
 
 javadocJar()
-
-if (deployVersion != null) {
-    publish()
-}
-