Fix rtyley#79 - Specify a version for maven-resources-plugin

Latest version I see in Maven Central (v2.6) seems to work?

$ java -version
java version "1.7.0_09"
OpenJDK Runtime Environment (IcedTea7 2.3.4) (7u9-2.3.4-0ubuntu1.12.10.1)
OpenJDK 64-Bit Server VM (build 23.2-b09, mixed mode)
$ mvn clean install
...
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2:04.906s
[INFO] Finished at: Fri Feb 01 09:00:17 GMT 2013
[INFO] Final Memory: 55M/690M
[INFO] ------------------------------------------------------------------------

Maven 3.0.4, Ubuntu 12.10

Not sure how this affects issue rtyley#78 but the manifest at
./agit/target/filtered-manifest/AndroidManifest.xml has the value
'android:versionCode="130200108"' which is fine...

rtyley#78
rtyley#79

Author: rtyley

agit/pom.xml

@@ -164,7 +164,9 @@
         </resources>
         <plugins>
             <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-resources-plugin</artifactId>
+                <version>2.6</version>
                 <executions>
                     <execution>
                         <phase>initialize</phase>