Update defaultSnapshotVersion to 1.6.255-SNAPSHOT

gradle.properties

@@ -5,7 +5,7 @@ org.gradle.caching=true
 org.gradle.java.installations.fromEnv=JDK_16,JDK_17,JDK_18,JDK_9,JDK_10,JDK_11,JDK_15
 
 cacheRedirectorEnabled=true
-defaultSnapshotVersion=1.5.255-SNAPSHOT
+defaultSnapshotVersion=1.6.255-SNAPSHOT
 
 # Enable JVM IR backend for kotlin-stdlib, kotlin-reflect, kotlin-test.
 #kotlin.build.useIRForLibraries=true

libraries/stdlib/src/kotlin/util/KotlinVersion.kt

@@ -79,5 +79,5 @@ public class KotlinVersion(val major: Int, val minor: Int, val patch: Int) : Com
 // this class is ignored during classpath normalization when considering whether to recompile dependencies in Kotlin build
 private object KotlinVersionCurrentValue {
     @kotlin.jvm.JvmStatic
-    fun get(): KotlinVersion = KotlinVersion(1, 5, 255) // value is written here automatically during build
+    fun get(): KotlinVersion = KotlinVersion(1, 6, 255) // value is written here automatically during build
 }