Fix adding duplicate tags

leapp/workflows/__init__.py

@@ -165,7 +165,7 @@ def __init__(self, logger=None, auto_reboot=False):
         self.description = self.description or type(self).__doc__
 
         for phase in self.phases:
-            phase.filter.tags += (self.tag,)
+            phase.filter.tags += (self.tag,) if self.tag not in phase.filter.tags else ()
             self._phase_actors.append((
                 phase,
                 # filters all actors with the give tags