[gnome-calendar] flatpak: Remove `gtk3` from gcr options

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

commit 363918dd3888b20dab7ba1254357a8e4c6d8c528
Author: Dimitrios Christidis <dimitrios christidis me>
Date:   Wed Sep 14 22:39:26 2022 +0200

    flatpak: Remove `gtk3` from gcr options
    
    Refer to https://gitlab.gnome.org/GNOME/gcr/-/issues/100

 build-aux/flatpak/org.gnome.Calendar.json | 1 -
 1 file changed, 1 deletion(-)
---
diff --git a/build-aux/flatpak/org.gnome.Calendar.json b/build-aux/flatpak/org.gnome.Calendar.json
index 0027e31a..07f5510b 100644
--- a/build-aux/flatpak/org.gnome.Calendar.json
+++ b/build-aux/flatpak/org.gnome.Calendar.json
@@ -123,7 +123,6 @@
             "buildsystem" : "meson",
             "config-opts" : [
                 "-Dgtk_doc=false",
-                "-Dgtk3=false",
                 "-Dintrospection=false",
                 "-Dvapi=false"
             ],