Add missing since (#1682)

No JIRA, but is annoying that faily modern
interfaces have no since set properly.

Arrived with commit:
2bb1228de6

maven-model-builder/src/main/java/org/apache/maven/model/interpolation/ModelVersionProcessor.java

@@ -25,6 +25,8 @@ import org.apache.maven.model.building.ModelBuildingRequest;
 /**
  * Allows a fixed set of properties that are valid inside a version and that could be overwritten for example on the
  * commandline
+ *
+ * @since 3.8.5
  */
 public interface ModelVersionProcessor {