Update dependency com.icegreen:greenmail to v2

Author: renovate[bot]

pom.xml

@@ -103,7 +103,7 @@ OF THE POSSIBILITY OF SUCH DAMAGE.
     <dependency>
       <groupId>com.icegreen</groupId>
       <artifactId>greenmail</artifactId>
-      <version>1.5.0</version>
+      <version>2.1.2</version>
       <scope>test</scope>
       <exclusions>
         <exclusion>