Bug: changed import url

[Serdar]

contrib/data_filter_elasticsearch/cmd/opa-es-filtering have these link to import
"github.com/open-policy-agent/contrib/data_filter_elasticsearch/internal/api"
"github.com/open-policy-agent/contrib/data_filter_elasticsearch/internal/es"
however these links are changed to:
"github.com/open-policy-agent/contrib/tree/master/data_filter_elasticsearch/internal/api"
"github.com/open-policy-agent/contrib/tree/master/data_filter_elasticsearch/internal/es"

[Anders Eknert]

Cleaning up 🧹 I don't think this is an issue any more, but let me know if it is.