docs: remove outdated warning

Warning message about filters on OWNERS files not working for the approve
plugin links to <kubernetes/test-infra#7690>, which
appears to be resolved.

Author: jeremysprofile

contributors/guide/owners.md

@@ -92,9 +92,6 @@ filters:
 
 Instead, set a `.*` key inside `filters` (as shown in the previous example).
 
-**WARNING**: The `approve` plugin [does not currently respect `filters`][test-infra-7690].
-Until that is fixed, `filters` should only be used for the `labels` key (as shown in the above example).
-
 
 #### Emeritus