[gnome-calendar] application: Fix tm -> GDateTime month conversion

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 02cd9b053e124b6f510b677fd6e7ab2bdf577d04
Author: Michael Webster <miketwebster gmail com>
Date:   Tue Dec 14 14:38:21 2021 -0500

    application: Fix tm -> GDateTime month conversion
    
    The month argument for g_date_time_new() is 1-based,
    while the tm struct is 0-based.
    
    Follow-up to:
    a0aa36b6d2ca5
    
    ref:
    https://pubs.opengroup.org/onlinepubs/7908799/xsh/time.h.html

 src/gui/gcal-application.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/gui/gcal-application.c b/src/gui/gcal-application.c
index 0bd32816..75013b90 100644
--- a/src/gui/gcal-application.c
+++ b/src/gui/gcal-application.c
@@ -416,7 +416,7 @@ gcal_application_command_line (GApplication            *app,
 
           initial_date = g_date_time_new (gcal_context_get_timezone (self->context),
                                           result.tm_year + 1900,
-                                          result.tm_mon,
+                                          result.tm_mon + 1,
                                           result.tm_mday,
                                           result.tm_hour,
                                           result.tm_min,