Upgrade to VMware Tanzu (Pivotal) GemFire 9.15.0.

Author: jxblum

gradle.properties

@@ -7,7 +7,7 @@ findbugsVersion=3.0.2
 #micrometerVersion=1.9.0-SNAPSHOT
 multithreadedtcVersion=1.01
 pivotalCloudCacheVersion=1.14.4
-pivotalGemFireVersion=9.10.15
+pivotalGemFireVersion=9.15.0
 springVersion=6.0.0-M4
 springBootVersion=3.0.0-SNAPSHOT
 springCloudBindingsVersion=1.9.0