fix(updater): do not allow or set custom provider

internal/configuration/settings/updater.go

@@ -43,6 +43,10 @@ func (u Updater) Validate() (err error) {
 	for i, provider := range u.Providers {
 		valid := false
 		for _, validProvider := range constants.AllProviders() {
+			if validProvider == constants.Custom {
+				continue
+			}
+
 			if provider == validProvider {
 				valid = true
 				break

internal/configuration/sources/env/updater.go

@@ -22,7 +22,12 @@ func readUpdater() (updater settings.Updater, err error) {
 	}
 
 	// TODO use current provider being used
-	updater.Providers = constants.AllProviders()
+	for _, provider := range constants.AllProviders() {
+		if provider == constants.Custom {
+			continue
+		}
+		updater.Providers = append(updater.Providers, provider)
+	}
 
 	return updater, nil
 }