Upgrade to Apache Geode 1.15.0.

Resolves gh-604.

Author: jxblum

spring-data-geode/pom.xml

@@ -22,7 +22,11 @@
 		<project.root>${basedir}/..</project.root>
 		<maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
 		<maven-toolchains-plugin.version>3.0.0</maven-toolchains-plugin.version>
-		<geode.version>1.14.4</geode.version>
+		<geode.version>1.15.0</geode.version>
+<!--
+		<geode.version>[1.15.0,1.16.0)</geode.version>
+		<geode.version>[1.15.0,1.15.0-build.1038)</geode.version>
+-->
 		<spring-test-data-geode.version>0.0.28</spring-test-data-geode.version>
 	</properties>