[Gradle, JS] Update package json only if version of dependency changed

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/yarn/YarnImportedPackagesVersionResolver.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
@@ -89,7 +89,7 @@ class YarnImportedPackagesVersionResolver(
         var doneSomething = false
         map.iterator().forEachRemaining {
             val resolved = resolvedVersion[it.key]
-            if (resolved != null) {
+            if (resolved != null && it.value != resolved) {
                 it.setValue(resolved)
                 doneSomething = true
             }