Bump spring.version from 2.5.6 to 5.2.0.RELEASE

Bumps `spring.version` from 2.5.6 to 5.2.0.RELEASE.

Updates `spring-aop` from 2.5.6 to 5.2.0.RELEASE
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/commits/v5.2.0.RELEASE)

Updates `spring-beans` from 2.5.6 to 5.2.0.RELEASE
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/commits/v5.2.0.RELEASE)

Updates `spring-core` from 2.5.6 to 5.2.0.RELEASE
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/commits/v5.2.0.RELEASE)

Updates `spring-context` from 2.5.6 to 5.2.0.RELEASE
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/commits/v5.2.0.RELEASE)

Updates `spring-test` from 2.5.6 to 5.2.0.RELEASE
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/commits/v5.2.0.RELEASE)

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/pom.xml b/pom.xml
index 31f8796..4a6d72a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -97,7 +97,7 @@
         <servicemix.legal.version>1.0</servicemix.legal.version>
         <servicemix.specs.version>1.4-SNAPSHOT</servicemix.specs.version>
         <spring.osgi.version>1.2.0-rc1</spring.osgi.version>
-        <spring.version>2.5.6</spring.version>
+        <spring.version>5.2.0.RELEASE</spring.version>
         <sshd.version>1.0-SNAPSHOT</sshd.version>
         <woodstox.version>3.2.7_1</woodstox.version>
         <osgi.jmx.version>1.0-r6125-patched</osgi.jmx.version>