Bump spring-expression from 3.1.1.RELEASE to 5.2.21.RELEASE

Bumps [spring-expression](https://github.com/spring-projects/spring-framework) from 3.1.1.RELEASE to 5.2.21.RELEASE.
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](spring-projects/spring-framework@v3.1.1.RELEASE...v5.2.21.RELEASE)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

pom.xml

@@ -406,7 +406,7 @@
   <properties>
     <gs.version>2.2-SNAPSHOT</gs.version>
     <gt.version>8-SNAPSHOT</gt.version>
-    <spring.version>3.1.1.RELEASE</spring.version>
+    <spring.version>5.2.21.RELEASE</spring.version>
     <spring.security.version>3.1.0.RELEASE</spring.security.version>
     <jetty.version>6.1.23</jetty.version>
     <ant.version>1.6.5</ant.version>