XWIKI-20047: Upgrade to Greenmail 1.6.10

pom.xml

@@ -803,7 +803,7 @@
       <dependency>
         <groupId>com.icegreen</groupId>
         <artifactId>greenmail-junit5</artifactId>
-        <version>1.6.9</version>
+        <version>1.6.10</version>
       </dependency>
 
       <!-- Make sure to use a version of the Jetty client libraries matching the Jetty version we package -->