Upgrade to Spring Boot 2.6.13.

Author: jxblum

gradle.properties

@@ -8,7 +8,7 @@ multithreadedtcVersion=1.01
 pivotalCloudCacheVersion=1.14.5
 pivotalGemFireVersion=9.10.16
 springVersion=5.3.23
-springBootVersion=2.6.13-SNAPSHOT
+springBootVersion=2.6.13
 springCloudBindingsVersion=1.8.1
 springDataBomVersion=2021.1.7
 springDataGeodeVersion=2.6.7