Require wp 4.0 for plugins update test

The plugins update-check api doesn't actually work with older versions
of WordPress, for two reasons:

The first is that the no_updates field wasn't added til 4.0 The second
is that the request that WP itself makes to the plugins update API is
missing &all=true which causes the API to always return an empty
response in my testing.

Both of these were added in 4.0 here:
WordPress/wordpress-develop@b00097b

Author: mrsdizzie

features/plugin.feature

@@ -811,6 +811,7 @@ Feature: Manage WordPress plugins
       5.5
       """
 
+  @require-wp-4.0
   Scenario: Show plugin update as unavailable if it doesn't meet WordPress requirements
     Given a WP install
     And a wp-content/plugins/example/example.php file:
@@ -857,6 +858,7 @@ Feature: Manage WordPress plugins
       Warning: example: This update requires WordPress version 100
       """
 
+ @require-wp-4.0
  Scenario: Show plugin update as unavailable if it doesn't meet PHP requirements
     Given a WP install
     And a wp-content/plugins/example/example.php file: