Merge pull request #1638 from rm3l/dependabot/gradle/backend/backend-kotlin-64350ca3f7

chore(deps): bump the backend-kotlin group across 1 directory with 2 updates

Author: rm3l

backend/build.gradle

@@ -24,8 +24,8 @@
 plugins {
     id "pl.allegro.tech.build.axion-release" version "1.21.4"
     id "com.diffplug.spotless" version "8.10.4"
-    id "org.jetbrains.kotlin.jvm" version "2.1.21"
-    id "org.jetbrains.kotlin.plugin.allopen" version "2.1.21"
+    id "org.jetbrains.kotlin.jvm" version "2.4.21"
+    id "org.jetbrains.kotlin.plugin.allopen" version "2.4.21"
 }
 
 ext {
@@ -96,15 +96,15 @@ subprojects {
 
     compileKotlin {
         kotlinOptions {
-            languageVersion = "1.6"
-            freeCompilerArgs = ["-Xjsr305=strict", "-Xopt-in=kotlin.RequiresOptIn"]
+            languageVersion = "2.0"
+            freeCompilerArgs = ["-Xjsr305=strict", "-opt-in=kotlin.RequiresOptIn"]
             jvmTarget = JavaVersion.VERSION_17.majorVersion
         }
     }
     compileTestKotlin {
         kotlinOptions {
-            languageVersion = "1.6"
-            freeCompilerArgs = ["-Xjsr305=strict", "-Xopt-in=kotlin.RequiresOptIn"]
+            languageVersion = "2.0"
+            freeCompilerArgs = ["-Xjsr305=strict", "-opt-in=kotlin.RequiresOptIn"]
             jvmTarget = JavaVersion.VERSION_17.majorVersion
         }
     }