Update Kotlin to 2.0.20

.gitignore

@@ -5,6 +5,7 @@ gradle.properties
 .fleet
 # But we need these
 !.idea/runConfigurations
+.kotlin
 
 # Ignore Gradle build output directory
 build

build.gradle.kts

@@ -1,3 +1,4 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
 import org.jetbrains.kotlin.gradle.tasks.KotlinJvmCompile
 import org.jlleitschuh.gradle.ktlint.KtlintExtension
 import org.jlleitschuh.gradle.ktlint.KtlintPlugin
@@ -43,12 +44,9 @@ subprojects {
     tasks {
         withType<KotlinJvmCompile> {
             dependsOn("ktlintFormat")
-            kotlinOptions {
-                jvmTarget = JavaVersion.VERSION_1_8.toString()
-
-                freeCompilerArgs += listOf(
-                    "-Xcontext-receivers",
-                )
+            compilerOptions {
+                jvmTarget = JvmTarget.JVM_1_8
+                freeCompilerArgs.add("-Xcontext-receivers")
             }
         }
     }

gradle/libs.versions.toml

@@ -1,5 +1,5 @@
 [versions]
-kotlin = "1.9.10"
+kotlin = "2.0.20"
 coroutines = "1.7.3"
 serialization = "1.6.0"
 okhttp = "5.0.0-alpha.14" # Major version is locked by Tachiyomi extensions

server/build.gradle.kts

@@ -141,9 +141,8 @@ tasks {
     }
 
     withType<KotlinJvmCompile> {
-        kotlinOptions {
-            freeCompilerArgs +=
-                listOf(
+        compilerOptions {
+            freeCompilerArgs.add(
                 "-opt-in=kotlinx.serialization.ExperimentalSerializationApi",
             )
         }