Updated debian changelog for version 6.4.1

debian/changelog

+swh-model (6.4.1-1~swh1) unstable-swh; urgency=medium
+
+  * New upstream release 6.4.1     - (tagged by Valentin Lorentz
+    <vlorentz@softwareheritage.org> on 2022-08-31 10:27:27 +0200)
+  * Upstream changes:     - v6.4.1     - * Add support for old dicts in
+    RawExtrinsicMetadata.from_dict
+
+ -- Software Heritage autobuilder (on jenkins-debian1) <jenkins@jenkins-debian1.internal.softwareheritage.org>  Wed, 31 Aug 2022 08:31:28 +0000
+
 swh-model (6.4.0-1~swh1) unstable-swh; urgency=medium
 
   * New upstream release 6.4.0     - (tagged by Valentin Lorentz