replace maven version to latest one

releng/org.yakindu.sct.releng/pom.xml

@@ -112,8 +112,8 @@
 					<version>${tycho-version}</version>
 					<configuration>
 						<encoding>UTF-8</encoding>
-						<source>6.0</source>
-						<target>6.0</target>
+						<source>7.0</source>
+						<target>7.0</target>
 						<extraClasspathElements>
 							<extraClasspathElement>
 								<groupId>com.google.inject.extensions</groupId>
@@ -163,7 +163,7 @@
 				<plugin>
 					<groupId>org.eclipse.xtend</groupId>
 					<artifactId>xtend-maven-plugin</artifactId>
-					<version>2.9.0</version>
+					<version>2.8.3</version>
 					<configuration>
 						<!-- need to prefix by basedir to generate to currently built module -->
 						<outputDirectory>${basedir}/xtend-gen</outputDirectory>