Release version 40.0

I made 40 release yesterday by mistake. Let's use 40.0 instead to
ensure the correct sort order.

Fixes: GNOME/nautilus#1807

NEWS

-Major changes in 40
-===================
+Major changes in 40.0
+=====================
 * Translation updates
 
 Major changes in 40.rc

data/org.gnome.Nautilus.appdata.xml.in.in

@@ -27,7 +27,7 @@
   <url type="translate">https://wiki.gnome.org/TranslationProject</url>
   <launchable type="desktop-id">@appid@.desktop</launchable>
   <releases>
-    <release version="40" date="2021-03-19" />
+    <release version="40.0" date="2021-03-20" />
   </releases>
   <project_group>GNOME</project_group>
   <project_license>GPL-2.0+</project_license>

meson.build

@@ -4,7 +4,7 @@ project('nautilus', 'c',
   # Do not forget when releasing:
   #  * Update version in data/org.gnome.Nautilus.appdata.xml.in.in
   #  * Update GTK-based codes over src/gtk/gtk-code-generator.sh
-  version: '40.1',
+  version: '40.0',
 
   meson_version: '>= 0.49.0',
   license: 'GPL3+'