[Releng] Implement ExternalResource.createMarker(String, Map<String, ?
extends Object>) with slightly different signature
diff --git a/plugins/org.eclipse.oomph.resources/src/org/eclipse/oomph/internal/resources/ExternalResource.java b/plugins/org.eclipse.oomph.resources/src/org/eclipse/oomph/internal/resources/ExternalResource.java
index 4a4e448..01834ee 100644
--- a/plugins/org.eclipse.oomph.resources/src/org/eclipse/oomph/internal/resources/ExternalResource.java
+++ b/plugins/org.eclipse.oomph.resources/src/org/eclipse/oomph/internal/resources/ExternalResource.java
@@ -144,7 +144,7 @@
     throw new ReadOnlyException();
   }
 
-  public IMarker createMarker(String type, Map<String, Object> attributes) throws CoreException
+  public IMarker createMarker(String type, Map<String, ? extends Object> attributes) throws CoreException
   {
     throw new ReadOnlyException();
   }