Upgrade to Gradle 9.7.0

Fix a deprecation warning surfaced by the upgrade: referencing the
version catalog as a bare `libs` inside the root build.gradle's
cross-project configure(allprojects) {} block relied on implicit
parent-project property lookup, which is deprecated and will fail in
Gradle 10. Use rootProject.libs explicitly instead.

Signed-off-by: Roy Clarkson <roy.clarkson@broadcom.com>

Author: royclarkson

build.gradle

@@ -70,7 +70,7 @@ configure(allprojects - [project(':spring-cloud-open-service-broker-docs')]) {
 	}
 
 	dependencies {
-		checkstyle(libs.spring.javaformat.checkstyle)
+		checkstyle(rootProject.libs.spring.javaformat.checkstyle)
 	}
 
 	test {
@@ -235,6 +235,6 @@ configure(rootProject) {
 }
 
 wrapper {
-	gradleVersion = "9.6.1"
+	gradleVersion = "9.7.0"
 	distributionType = Wrapper.DistributionType.ALL
 }

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.6.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.7.0-all.zip
 networkTimeout=10000
 retries=0
 retryBackOffMs=500