Upgrade Spring Framework to 5.3.26 (#2633)

Author: garyrussell

build.gradle

@@ -65,10 +65,10 @@ ext {
 	mockitoVersion = '4.5.1'
 	reactorVersion = '2020.0.28'
 	scalaVersion = '2.13'
-	springBootVersion = '2.7.8' // docs module
+	springBootVersion = '2.7.9' // docs module
 	springDataVersion = '2021.2.8'
 	springRetryVersion = '1.3.4'
-	springVersion = '5.3.25'
+	springVersion = '5.3.26'
 	zookeeperVersion = '3.6.3'
 
 	idPrefix = 'kafka'