small optimization of extensions.gradle

gradle/templates/mppJsProject.gradle

@@ -0,0 +1,31 @@
+project.version = "$version"
+project.group = "$group"
+
+apply from: "$mpp_publish"
+
+kotlin {
+    js (IR) {
+        browser()
+        nodejs()
+    }
+
+    sourceSets {
+        commonMain {
+            dependencies {
+                implementation libs.kotlin
+                api libs.kotlin.serialization
+            }
+        }
+        commonTest {
+            dependencies {
+                implementation libs.kotlin.test.common
+                implementation libs.kotlin.test.annotations.common
+            }
+        }
+        jsTest {
+            dependencies {
+                implementation libs.kotlin.test.js
+            }
+        }
+    }
+}