Update build scripts.

Author: gk-brown

gradle.properties

@@ -0,0 +1 @@
+kotlinVersion = 1.9.23

settings.gradle

@@ -1,11 +1,3 @@
-pluginManagement {
-    plugins {
-        id 'org.jetbrains.kotlin.jvm' version '1.9.23'
-    }
-}
-plugins {
-    id 'org.gradle.toolchains.foojay-resolver-convention' version '0.5.0'
-}
 rootProject.name = 'Sierra'
 
 include 'sierra', 'sierra-test'

sierra-test/build.gradle

@@ -14,23 +14,16 @@
 
 plugins {
     id 'application'
-    id 'org.jetbrains.kotlin.jvm'
+    id 'org.jetbrains.kotlin.jvm' version "${kotlinVersion}"
 }
 
 dependencies {
     implementation project(':sierra')
 
     implementation 'com.formdev:flatlaf:3.4.1'
     implementation 'com.formdev:flatlaf-extras:3.4.1'
-    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
 }
 
 jar {
     archiveFileName = "${project.name}.jar"
 }
-repositories {
-    mavenCentral()
-}
-kotlin {
-    jvmToolchain(17)
-}

sierra/build.gradle

@@ -13,7 +13,7 @@
  */
 
 plugins {
-    id 'org.jetbrains.kotlin.jvm'
+    id 'org.jetbrains.kotlin.jvm' version "${kotlinVersion}"
     id 'org.jetbrains.dokka' version '1.9.20'
 }