Declare Sprig 'plugins-snapshot' Repository to resolve GemFire artifacts.

spring-session-data-gemfire/spring-session-data-gemfire.gradle

@@ -3,6 +3,18 @@ apply from: MAVEN_POM_EDITOR_GRADLE
 
 description = "Spring Session for Pivotal GemFire"
 
+repositories {
+	maven {
+		url 'https://repo.spring.io/plugins-snapshot'
+		if (project.hasProperty('artifactoryUsername')) {
+			credentials {
+				username "$artifactoryUsername"
+				password "$artifactoryPassword"
+			}
+		}
+	}
+}
+
 dependencies {
 
 	compile(project(':spring-session-data-geode')) {