Mark components example as WIP

Since the required implementation for the components example has not
been merged yet, we must inform the users that this example is a work in
progress.

Signed-off-by: Alex Pyrgiotis <apyrgio@arrikto.com>

examples/components.md

@@ -1,5 +1,8 @@
 # Demo: Components
 
+_(Note: This is still a work in progress. Tracking KEP:
+https://github.com/kubernetes/enhancements/pull/1803)_
+
 Suppose you've written a very simple Web application:
 
 ```yaml