Explicitly say I'm happy to update the role

Added a note to say the role isn't comprehensive and that I'm happy to change
it - it should be assumed by the author contact section but just in case...

README.md

@@ -20,6 +20,10 @@ If the role is run without updating filesystems_configuration_mounted to
 'mounted' filesystems will need to be manually remounted or the server rebooted
 to pick up the new configuration. The current setting is the safe default.
 
+The role isn't comprehensive - there are other things living in /etc/ that need
+moving which might affect you - I'm happy to update the role if you encounter
+any.
+
 Role Variables
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