Merge pull request #736 from rabbitmq/dependabot/maven/org.codehaus.groovy-groovy-all-2.4.21

Bump groovy-all from 2.4.8 to 2.4.21

Author: acogoluegnes

pom.xml

@@ -72,7 +72,7 @@
     <maven.resources.plugin.version>3.2.0</maven.resources.plugin.version>
     <maven.source.plugin.version>3.2.1</maven.source.plugin.version>
     <groovy.maven.plugin.version>2.1.1</groovy.maven.plugin.version>
-    <groovy.all.version>2.4.8</groovy.all.version>
+    <groovy.all.version>2.4.21</groovy.all.version>
     <keytool.maven.plugin.version>1.5</keytool.maven.plugin.version>
     <build.helper.maven-plugin.version>3.3.0</build.helper.maven-plugin.version>
     <maven.compiler.plugin.version>3.8.1</maven.compiler.plugin.version>