Added an @Execute annotation to RunMojo

Update RunMojo to include an @Execute annotation. Allows the use of
`mvn spring-boot:run` without having to compile/package first. Now a
command like `mvn clean spring-boot:run` works.

The phase for @Execute annotation is along the lines of what is used
for the `jetty:run` plugin.

spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/RunMojo.java

@@ -30,6 +30,7 @@ import org.apache.maven.model.Resource;
 import org.apache.maven.plugin.AbstractMojo;
 import org.apache.maven.plugin.MojoExecutionException;
 import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Execute;
 import org.apache.maven.plugins.annotations.LifecyclePhase;
 import org.apache.maven.plugins.annotations.Mojo;
 import org.apache.maven.plugins.annotations.Parameter;
@@ -43,6 +44,7 @@ import org.springframework.boot.loader.tools.MainClassFinder;
  * @author Phillip Webb
  */
 @Mojo(name = "run", requiresProject = true, defaultPhase = LifecyclePhase.VALIDATE, requiresDependencyResolution = ResolutionScope.TEST)
+@Execute(phase=LifecyclePhase.TEST_COMPILE)
 public class RunMojo extends AbstractMojo {
 
 	/**