Upgrade to Spring Framework 5.3.20.

Author: jxblum

gradle.properties

@@ -2,7 +2,7 @@ org.gradle.jvmargs=-Xmx2g -Dfile.encoding=UTF-8
 deployDocsHost=docs-ip.spring.io
 apacheGeodeVersion=1.14.4
 findbugsVersion=3.0.2
-springVersion=5.3.19
+springVersion=5.3.20
 springBootVersion=2.7.0-M3
 springDataBomVersion=2021.2.0-RC1
 springDataCommonsVersion=2.7.0-RC1