fix: update expected error-message

Signed-off-by: Anton Bronnikov <anton@northernforest.nl>

ovh/configuration_test.go

@@ -64,7 +64,7 @@ func TestConfigFromNonExistingFile(t *testing.T) {
 
 	client := Client{}
 	err := client.loadConfig("ovh-eu")
-	td.CmpString(t, err, `missing authentication information, you need to provide at least an application_key/application_secret, or client_id/client_secret, or access_token`)
+	td.CmpString(t, err, `missing authentication information, you need to provide one of the following: application_key/application_secret, client_id/client_secret, or access_token`)
 }
 
 func TestConfigFromInvalidINIFile(t *testing.T) {