Bump spring-beans from 2.5.6 to 5.2.20.RELEASE

Bumps [spring-beans](https://github.com/spring-projects/spring-framework) from 2.5.6 to 5.2.20.RELEASE.
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/commits/v5.2.20.RELEASE)

---
updated-dependencies:
- dependency-name: org.springframework:spring-beans
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/pom.xml b/pom.xml
index ec59640..8d25e8c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -63,7 +63,7 @@
     <junit.version>4.10</junit.version>
 
     <jgroups.version>3.0.4.Final</jgroups.version>
-    <spring.version>2.5.6</spring.version>
+    <spring.version>5.2.20.RELEASE</spring.version>
 
     <directmemory.lightning.scmPubCheckoutDirectory>${user.home}/directmemory-lightning-site-content</directmemory.lightning.scmPubCheckoutDirectory>
     <scmSkipDeletedFiles>false</scmSkipDeletedFiles>