Use standard Java annotation syntax instead of custom Javadoc tag

For better support by building tools.
As reported by @KnustJohn_twitter , the custom
[@phase](https://maven.apache.org/plugin-tools/maven-plugin-tools-java/index.html)
Javadoc tag made NetBeans fail on Javadoc generation for the
GitRevmavenTask class.
Using instead standard Java 5
[annotations](https://maven.apache.org/plugin-tools/maven-plugin-plugin/examples/using-annotations.html#POM_configuration)
this is no more an issue.

libbuild/GitRevMavenTask/src/GitRevMavenTask.java

@@ -9,6 +9,7 @@
 import org.apache.maven.plugin.MojoExecutionException;
 import org.apache.maven.plugin.logging.Log;
 import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.LifecyclePhase;
 import org.apache.maven.plugins.annotations.Mojo;
 import org.apache.maven.plugins.annotations.Parameter;
 import org.apache.maven.project.MavenProject;
@@ -25,9 +26,8 @@
  * Maven plugin to create property with YaCy release number,
  * a 4 digit number based on commits to the Git repository
  *
- * @phase initialize
  */
-@Mojo(name = "create")
+@Mojo(name = "create", defaultPhase = LifecyclePhase.INITIALIZE)
 public class GitRevMavenTask extends AbstractMojo {
 
     @Component