[KPM] :kotlin-gradle-plugin-idea: Set language- and apiVersion to 1.4

^KT-51262

libraries/tools/kotlin-gradle-plugin-idea/build.gradle.kts

@@ -2,6 +2,13 @@ plugins {
     kotlin("jvm")
 }
 
+kotlin {
+    sourceSets.configureEach {
+        languageSettings.languageVersion = "1.4"
+        languageSettings.apiVersion = "1.4"
+    }
+}
+
 dependencies {
     implementation(kotlinStdlib())
 }