[MASSEMBLY-974] Drop deprecated repository element (#113)

As a followup for deprecation MASSEMBLY-957 in version 3.4.0, the deprecated element is being dropped.

As a consequence, this removes deprecated MAT as well.

--

https://issues.apache.org/jira/browse/MASSEMBLY-974

Author: cstamas

pom.xml

@@ -63,7 +63,7 @@ under the License.
 
   <properties>
     <javaVersion>8</javaVersion>
-    <mdoVersion>2.1.1</mdoVersion>
+    <mdoVersion>2.2.0</mdoVersion>
     <mavenVersion>3.2.5</mavenVersion>
     <slf4jVersion>1.7.5</slf4jVersion>
     <mavenFilteringVersion>3.3.0</mavenFilteringVersion>
@@ -145,11 +145,6 @@ under the License.
       <artifactId>maven-common-artifact-filters</artifactId>
       <version>3.3.1</version>
     </dependency>
-    <dependency>
-      <groupId>org.apache.maven.shared</groupId>
-      <artifactId>maven-artifact-transfer</artifactId>
-      <version>0.13.1</version>
-    </dependency>
 
     <dependency>
       <groupId>org.codehaus.plexus</groupId>