Avoid sealing shaded jar (#10)

diff --git a/stresso/pom.xml b/stresso/pom.xml
index bf31c57..bc3c66d 100644
--- a/stresso/pom.xml
+++ b/stresso/pom.xml
@@ -184,6 +184,13 @@
                   </excludes>
                 </filter>
               </filters>
+              <transformers>
+                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                  <manifestEntries>
+                    <Sealed>False</Sealed>
+                  </manifestEntries>
+                </transformer>
+              </transformers>
             </configuration>
           </execution>
         </executions>