mark pf4j.jar as multi release library (#305)

pf4j/pom.xml

@@ -52,6 +52,17 @@
                     </execution>
                 </executions>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <configuration>
+                    <archive>
+                        <manifestEntries>
+                            <Multi-Release>true</Multi-Release>
+                        </manifestEntries>
+                    </archive>
+                </configuration>
+            </plugin>
         </plugins>
     </build>