[gnome-notes] appdata: Fix release 40.0's release date

[Isaque Galdino de Araujo <igaldino src gnome org>]

commit d18d360837c3db7be1d6b63e91bab22f70ec2d2c
Author: Felix Riemann <friemann gnome org>
Date:   Wed Apr 7 19:33:24 2021 +0200

    appdata: Fix release 40.0's release date
    
    The transposed month digits make GNOME Software log warnings.

 data/appdata/org.gnome.Notes.appdata.xml.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/data/appdata/org.gnome.Notes.appdata.xml.in b/data/appdata/org.gnome.Notes.appdata.xml.in
index 2549d8f..339c608 100644
--- a/data/appdata/org.gnome.Notes.appdata.xml.in
+++ b/data/appdata/org.gnome.Notes.appdata.xml.in
@@ -39,7 +39,7 @@
   </screenshots>
 
   <releases>
-    <release date="2021-30-20" version="40.0">
+    <release date="2021-03-20" version="40.0">
       <description>
         <p>This release brings the following improvements:</p>
         <ul>