Bump spring-beans from 4.3.16.RELEASE to 5.2.20.RELEASE

Bumps [spring-beans](https://github.com/spring-projects/spring-framework) from 4.3.16.RELEASE to 5.2.20.RELEASE.
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/compare/v4.3.16.RELEASE...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 01675aa..2fcf218 100644
--- a/pom.xml
+++ b/pom.xml
@@ -35,7 +35,7 @@
         <java.source.version>1.8</java.source.version>
         <java.target.version>1.8</java.target.version>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <spring.version>4.3.16.RELEASE</spring.version>
+        <spring.version>5.2.20.RELEASE</spring.version>
         <rocket.version>4.9.3</rocket.version>
         <prometheus.version>0.12.0</prometheus.version>
     </properties>