Test our Gradle plugin against Gradle 7.3

Closes gh-28679

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/junit/GradleCompatibilityExtension.java

@@ -48,13 +48,13 @@ final class GradleCompatibilityExtension implements TestTemplateInvocationContex
 	static {
 		JavaVersion javaVersion = JavaVersion.current();
 		if (javaVersion.isCompatibleWith(JavaVersion.VERSION_17)) {
-			GRADLE_VERSIONS = Arrays.asList("7.2");
+			GRADLE_VERSIONS = Arrays.asList("7.2", "7.3");
 		}
 		else if (javaVersion.isCompatibleWith(JavaVersion.VERSION_16)) {
-			GRADLE_VERSIONS = Arrays.asList("7.0.2", "7.1.1", "7.2");
+			GRADLE_VERSIONS = Arrays.asList("7.0.2", "7.1.1", "7.2", "7.3");
 		}
 		else {
-			GRADLE_VERSIONS = Arrays.asList("6.8.3", "current", "7.0.2", "7.1.1", "7.2");
+			GRADLE_VERSIONS = Arrays.asList("6.8.3", "current", "7.0.2", "7.1.1", "7.2", "7.3");
 		}
 	}
 

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/junit/GradleMultiDslExtension.java

@@ -63,7 +63,7 @@ public class GradleMultiDslExtension implements TestTemplateInvocationContextPro
 			GradleBuild gradleBuild = new GradleBuild(this.dsl);
 			JavaVersion javaVersion = JavaVersion.current();
 			if (javaVersion.isCompatibleWith(JavaVersion.VERSION_17)) {
-				gradleBuild.gradleVersion("7.2");
+				gradleBuild.gradleVersion("7.3");
 			}
 			else if (javaVersion.isCompatibleWith(JavaVersion.VERSION_16)) {
 				gradleBuild.gradleVersion("7.0.2");