[balsa] Update POTFILES.in

[Piotr Drąg <piotrdrag src gnome org>]

commit 591bc933e64827a5d4e5b13842d2577c2de7ce79
Author: Piotr Drąg <piotrdrag gmail com>
Date:   Sun Aug 21 13:04:27 2022 +0200

    Update POTFILES.in

 po/POTFILES.in | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 7fbab7de8..254558838 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -60,6 +60,7 @@ libbalsa/server.c
 libbalsa/server-config.c
 libbalsa/smtp-server.c
 libbalsa/source-viewer.c
+libbalsa/system-tray.c
 libbalsa/x509-cert-widget.c
 libinit_balsa/assistant_helper.c
 libinit_balsa/assistant_init.c