Bump groovy-all from 1.8.0 to 2.4.21

diff --git a/pom.xml b/pom.xml
index 5f34c78..ad337b1 100644
--- a/pom.xml
+++ b/pom.xml
@@ -69,7 +69,7 @@
     -->
     <mavenPluginPluginVersion>3.5</mavenPluginPluginVersion>
     <plexusCompilerVersion>2.8.8</plexusCompilerVersion>
-    <groovyVersion>1.8.0</groovyVersion>
+    <groovyVersion>2.4.21</groovyVersion>
     <groovyEclipseCompilerVersion>2.7.0-01</groovyEclipseCompilerVersion>
     <groovy-eclipse-batch>2.0.4-04</groovy-eclipse-batch>
     <plexus-java.version>1.0.7</plexus-java.version>