Change annotation target type to field. (#6)

Signed-off-by: Felix Klauke <[email protected]>

src/main/java/de/felix_klauke/guice/extension/injection/logback/annotation/InjectLogback.java

@@ -33,6 +33,6 @@
  * @author Felix Klauke <[email protected]>
  */
 @Retention(RetentionPolicy.RUNTIME)
-@Target(ElementType.TYPE)
+@Target(ElementType.FIELD)
 public @interface InjectLogback {
 }