Prepare next development iteration.

Set Spring Boot version to 2.6.13-SNAPSHOT.

Set version to 1.6.13-SNAPSHOT.

Author: jxblum

gradle.properties

@@ -8,7 +8,7 @@ multithreadedtcVersion=1.01
 pivotalCloudCacheVersion=1.14.5
 pivotalGemFireVersion=9.10.16
 springVersion=5.3.23
-springBootVersion=2.6.12
+springBootVersion=2.6.13-SNAPSHOT
 springCloudBindingsVersion=1.8.1
 springDataBomVersion=2021.1.7
 springDataGeodeVersion=2.6.7
@@ -17,4 +17,4 @@ springSessionBomVersion=2021.1.3
 springSessionDataGeodeVersion=2.6.2
 springShellVersion=1.2.0.RELEASE
 testcontainersVersion=1.17.3
-version=1.6.12
+version=1.6.13-SNAPSHOT