Don't test on Gradle 9 yet because it breaks Java 11 support

Author: dennisameling

modules/openapi-generator-gradle-plugin/src/test/kotlin/GenerateTaskConfigurationCacheTest.kt

@@ -20,7 +20,7 @@ class GenerateTaskConfigurationCacheTest : TestBase() {
     }
 
     @DataProvider(name = "gradle_version_provider")
-    private fun gradleVersionProviderWithConfigurationCache(): Array<Array<String>> = arrayOf(arrayOf("9.0.0"), arrayOf("8.7"))
+    private fun gradleVersionProviderWithConfigurationCache(): Array<Array<String>> = arrayOf(arrayOf("8.14.4"), arrayOf("8.5"))
 
     @DataProvider(name = "gradle_version_provider_without_cc")
     private fun gradleVersionProviderWithoutConfigurationCache(): Array<Array<String>> = arrayOf(arrayOf("5.6.1"))

modules/openapi-generator-gradle-plugin/src/test/kotlin/GenerateTaskFromCacheTest.kt

@@ -22,7 +22,7 @@ class GenerateTaskFromCacheTest : TestBase() {
     }
 
     @DataProvider(name = "gradle_version_provider")
-    private fun gradleVersionProvider(): Array<Array<String>> = arrayOf(arrayOf("9.0.0"), arrayOf("8.7"))
+    private fun gradleVersionProvider(): Array<Array<String>> = arrayOf(arrayOf("8.14.4"), arrayOf("8.5"))
 
     // inputSpec tests
 

modules/openapi-generator-gradle-plugin/src/test/kotlin/GenerateTaskUpToDateTest.kt

@@ -9,7 +9,7 @@ import kotlin.test.assertEquals
 class GenerateTaskUpToDateTest : TestBase() {
 
     @DataProvider(name = "gradle_version_provider")
-    private fun gradleVersionProvider(): Array<Array<String>> = arrayOf(arrayOf("9.0.0"), arrayOf("8.7"))
+    private fun gradleVersionProvider(): Array<Array<String>> = arrayOf(arrayOf("8.14.4"), arrayOf("8.5"))
 
     // inputSpec tests
 

modules/openapi-generator-gradle-plugin/src/test/kotlin/ValidateTaskDslTest.kt

@@ -17,7 +17,6 @@ class ValidateTaskDslTest : TestBase() {
     @DataProvider(name = "gradle_version_provider")
     fun gradleVersionProvider(): Array<Array<String?>> = arrayOf(
         arrayOf(null), // uses the version of Gradle used to build the plugin itself
-        arrayOf("9.0.0"),
         arrayOf("8.5")
     )