Bump version number

NEWS

+Changes in version 3.20.1 are:
+ * Fix boolean logic error in ssh-agent
+ * Pass the correct argc to gkr_pam_client_run_operation [#766222]
+ * Look for both dlopen and dlsym when configuring [#766221]
+ * Fix .so link in gnome-keyring-3 man page [#767095]
+ * Die if the XDG session we were started under goes away [#768943]
+ * Shorten unlock keyring dialog title [#770170]
+ * Updated translations
+
 Changes in version 3.20.0 are:
  * Updated translations
 

configure.ac

 AC_INIT(gnome-keyring,
-        3.20.0,
+        3.20.1,
         [gnome-keyring-list@gnome.org],
         [gnome-keyring],
         [https://wiki.gnome.org/Projects/GnomeKeyring])