style: add comment for ProvidersResolver

Signed-off-by: Jesse Simpson <jesse.simpson36@gmail.com>

pkg/pusher/pusher.go

@@ -93,6 +93,7 @@ func (p Provider) Provides(scheme string) bool {
 // Providers is a collection of Provider objects.
 type Providers []Provider
 
+// ProvidersResolver is an interface for retrieving Pusher objects
 type ProvidersResolver interface {
 	ByScheme(scheme string) (Pusher, error)
 }