[ZEPPELIN-6133] Bump Groovy from 2.4.7 to 2.4.21

Bumps [org.codehaus.groovy:groovy-all](https://github.com/apache/groovy) from 2.4.7 to 2.4.21.
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Closes #4877 from dependabot[bot]/dependabot/maven/groovy/org.codehaus.groovy-groovy-all-2.4.21.

Signed-off-by: Cheng Pan <chengpan@apache.org>
(cherry picked from commit 3af2450)
Signed-off-by: Cheng Pan <chengpan@apache.org>

groovy/pom.xml

@@ -40,7 +40,7 @@
     <dependency>
         <groupId>org.codehaus.groovy</groupId>
         <artifactId>groovy-all</artifactId>
-        <version>2.4.7</version>
+        <version>2.4.21</version>
     </dependency>
 
   </dependencies>