fix: required_pkgs=self.required_pkgs

It looks like 'self.' has been forgotten.

Signed-off-by: Sergei Shtepa <sshtepa@noreply@resf.org>

iso/empanadas/empanadas/util/iso_utils.py

@@ -264,7 +264,7 @@ class IsoBuild:
                 releasever=self.release,
                 fullname=self.fullname,
                 shortname=self.shortname,
-                required_pkgs=required_pkgs,
+                required_pkgs=self.required_pkgs,
                 dist=self.disttag,
                 repos=self.repolist,
                 user_agent='{{ user_agent }}',