Use options.release = 8

Author: Lipen

build.gradle.kts

@@ -1,4 +1,6 @@
 import org.jetbrains.dokka.gradle.DokkaTaskPartial
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 // Use `-Pgroup=com.github.UnitTestBot` to emulate JitPack publishing.
 val groupProp = providers.gradleProperty("group").orNull
@@ -70,34 +72,14 @@ allprojects {
 
     tasks {
         withType<JavaCompile> {
-            sourceCompatibility = "1.8"
+            options.release = 8
             options.encoding = "UTF-8"
             options.compilerArgs.add("-Xlint:all")
         }
 
-        compileJava {
-            targetCompatibility = "1.8"
-        }
-        compileKotlin {
-            kotlinOptions {
-                jvmTarget = "1.8"
-            }
-        }
-
-        compileTestJava {
-            targetCompatibility = runtimeJavaVersion()
-        }
-        compileTestFixturesJava {
-            targetCompatibility = "1.8"
-        }
-        compileTestKotlin {
-            kotlinOptions {
-                jvmTarget = runtimeJavaVersion()
-            }
-        }
-        compileTestFixturesKotlin {
-            kotlinOptions {
-                jvmTarget = "1.8"
+        withType<KotlinCompile> {
+            compilerOptions {
+                jvmTarget = JvmTarget.JVM_1_8
             }
         }