debian/changelog

+nco (4.8.1-1) unstable; urgency=medium
+
+  * Update gbp.conf to use --source-only-changes by default.
+  * Move from experimental to unstable.
+
+ -- Bas Couwenberg <sebastic@debian.org>  Sun, 07 Jul 2019 08:47:09 +0200
+
 nco (4.8.1-1~exp1) experimental; urgency=medium
 
   * New upstream release.

debian/gbp.conf

@@ -17,3 +17,6 @@ pristine-tar = True
 
 [import-orig]
 rollback = False
+
+[buildpackage]
+pbuilder-options = --source-only-changes