fix various warnings

build.gradle

@@ -1,7 +1,11 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+import org.jetbrains.kotlin.gradle.tasks.KotlinJvmCompile
+
 plugins {
   id 'org.jetbrains.kotlin.jvm' version '2.0.0' apply false
   id 'org.jetbrains.dokka' version '1.8.10' apply false
   id 'org.jlleitschuh.gradle.ktlint' version '12.1.1' apply false
+  id 'com.gradle.plugin-publish' version '0.21.0' apply false
   id 'java-gradle-plugin'
   id 'java-library'
   id 'groovy'
@@ -39,9 +43,9 @@ subprojects {
     }
   }
 
-  tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).configureEach {
-    kotlinOptions {
-      jvmTarget = JavaVersion.VERSION_1_8
+  tasks.withType(KotlinJvmCompile).configureEach {
+    compilerOptions {
+      jvmTarget.set(JvmTarget.JVM_1_8)
     }
   }
 

gradle-versions-plugin/build.gradle

@@ -2,7 +2,7 @@ plugins {
   id 'org.jetbrains.kotlin.jvm'
   id 'org.jetbrains.dokka'
   id 'org.jlleitschuh.gradle.ktlint'
-  id 'com.gradle.plugin-publish' version '0.21.0'
+  id 'com.gradle.plugin-publish'
   id 'maven-publish'
   id 'java-gradle-plugin'
   id 'java-library'
@@ -13,7 +13,7 @@ group = GROUP
 version = VERSION_NAME
 
 // Write the plugin's classpath to a file to share with the tests
-task createClasspathManifest {
+tasks.register('createClasspathManifest') {
   def outputDir = file("$buildDir/$name")
 
   inputs.files sourceSets.main.runtimeClasspath
@@ -41,14 +41,16 @@ dependencies {
   testImplementation 'org.spockframework:spock-junit4:2.1-M2-groovy-3.0', { exclude module: 'groovy-all' } // Use localGroovy()
 }
 
-task docsJar(type: Jar, dependsOn: dokkaHtml) {
+tasks.register('docsJar', Jar) {
+  dependsOn dokkaHtml
   group = 'Publications'
   description = 'Create jar of documentation.'
   archiveClassifier = 'javadoc'
   from dokkaJavadoc.outputDirectory
 }
 
-task sourcesJar(type: Jar, dependsOn: classes) {
+tasks.register('sourcesJar', Jar) {
+  dependsOn classes
   group = 'Publications'
   description = 'Create jar of sources.'
   archiveClassifier = 'sources'

gradle-versions-plugin/src/test/groovy/com/github/benmanes/gradle/versions/DependencyUpdatesSpec.groovy

@@ -145,7 +145,7 @@ final class DependencyUpdatesSpec extends Specification {
     def project = singleProject()
     addRepositoryTo(project)
     addDependenciesTo(project)
-    project.configurations.all {
+    project.configurations.configureEach {
       resolutionStrategy {
         failOnDynamicVersions()
       }
@@ -189,6 +189,7 @@ final class DependencyUpdatesSpec extends Specification {
   @Unroll
   def 'Multi-project with dependencies on parent (#revision, #outputFormat)'() {
     given:
+    //noinspection GroovyUnusedAssignment
     def (rootProject, childProject) = multiProject()
     addRepositoryTo(rootProject)
     addDependenciesTo(rootProject)
@@ -620,7 +621,7 @@ final class DependencyUpdatesSpec extends Specification {
 
     when:
     def reporter = evaluate(project, 'milestone', null, 'build', null, null, false,
-      "", RELEASE_CANDIDATE.id, {config -> config.name.equals("upgradesFound")})
+      "", RELEASE_CANDIDATE.id, {config -> (config.name == "upgradesFound") })
     reporter.write()
 
     then: