User Agent do not contain bridge version, only client in format

pkg/pmapi/useragent.go

@@ -0,0 +1,37 @@
+// Copyright (c) 2020 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package pmapi
+
+import (
+	"fmt"
+	"runtime"
+)
+
+func formatUserAgent(clientName, clientVersion, os string) string {
+	client := ""
+	if clientName != "" {
+		client = clientName
+		if clientVersion != "" {
+			client += "/" + clientVersion
+		}
+	}
+	if os == "" {
+		os = runtime.GOOS
+	}
+	return fmt.Sprintf("%s (%s)", client, os)
+}