fix: notify pluggins can have no backends (fixes regression introduce…

…d by #51) (#83)

NotifyBackends can be empty ( as https://github.com/ovh/utask/blob/master/pkg/notify/notify.go#L51 )

Signed-off-by: Romain Beuque <romain.beuque@corp.ovh.com>

pkg/plugins/builtin/notify/notify.go

@@ -1,7 +1,6 @@
 package notify
 
 import (
-	"errors"
 	"fmt"
 	"sort"
 	"strings"
@@ -35,7 +34,8 @@ func validConfig(config interface{}) error {
 	cfg := config.(*Config)
 
 	if len(cfg.Backends) == 0 {
-		return errors.New("backends field can't be empty")
+		// if no backends defined, implies that all backends will be contacted
+		return nil
 	}
 
 	snames := notify.ListSendersNames()