Remove unused code from build script (#1190)

Remove descriptions related to the previously deleted unit-test module.

Author: nakamura-to

build.gradle.kts

@@ -15,7 +15,6 @@ val testJavaLangVersion: Int = project.properties["testJavaLangVersion"].toStrin
 
 val modularProjects: List<Project> = subprojects.filter { it.name.startsWith("doma-") }
 val integrationTestProjects: List<Project> = subprojects.filter { it.name.startsWith("integration-test-") }
-val unitTestProjects: List<Project> = subprojects.filter { it.name.startsWith("unit-test") }
 
 val encoding: String by project
 val isReleaseVersion = !version.toString().endsWith("SNAPSHOT")
@@ -278,17 +277,6 @@ configure(integrationTestProjects) {
     }
 }
 
-configure(unitTestProjects) {
-    apply(plugin = "java")
-    apply(plugin = "com.diffplug.spotless")
-
-    tasks {
-        test {
-            useJUnitPlatform()
-        }
-    }
-}
-
 rootProject.apply {
     release {
         newVersionCommitMessage.set("[Gradle Release Plugin] - [skip ci] new version commit: ")