Prepare release 6.4.0 [skip ci]

CHANGELOG

@@ -1,3 +1,5 @@
+Version 6.4.0 - 2022-05-02
+* Bug fixes (see mercurial logs for details)
 * Use invoice date to enforce sequence on customer invoice
 * Prevent delete tax identifier used on invoice
 * Raise a warning when validating supplier invoice with same reference

COPYRIGHT

@@ -1,6 +1,6 @@
-Copyright (C) 2008-2021 Cédric Krier.
+Copyright (C) 2008-2022 Cédric Krier.
 Copyright (C) 2008-2013 Bertrand Chenal.
-Copyright (C) 2008-2021 B2CK SPRL.
+Copyright (C) 2008-2022 B2CK SPRL.
 Copyright (C) 2004-2008 Tiny SPRL.
 
 This program is free software: you can redistribute it and/or modify

tryton.cfg

@@ -1,5 +1,5 @@
 [tryton]
-version=6.3.0
+version=6.4.0
 depends:
     account
     account_product