Bump groovy from 2.4.5 to 2.4.21

Bumps [groovy](https://github.com/apache/groovy) from 2.4.5 to 2.4.21.
- [Release notes](https://github.com/apache/groovy/releases)
- [Commits](https://github.com/apache/groovy/commits)

Signed-off-by: dependabot[bot] <support@github.com>

pom.xml

@@ -41,7 +41,7 @@
         <dependency>
             <groupId>org.codehaus.groovy</groupId>
             <artifactId>groovy</artifactId>
-            <version>2.4.5</version>
+            <version>2.4.21</version>
         </dependency>
 
         <dependency>