Upgrade trusted to use new facade method

Application facade has a new method for calling configuration values on
it. Use that instead of the old way. This is a breaking change if you're
using it from pylibjuju and we should probably be aware of that in the
future.

Luckily the fix is to just use the latest pylibjuju with this fix in it.

Author: SimonRichardson

juju/application.py

@@ -394,7 +394,18 @@ async def set_trusted(self, trust):
         log.debug(
             'Setting config for %s: %s', self.name, config)
 
-        return await app_facade.SetApplicationsConfig(args=[{
+        # Unfortunately we have to do this in a lazy fashion, attempting to use
+        # the method early will cause an error. Attempting to call this
+        # dynamically causes issues with how the client code is wired up... we
+        # end up with a missing _toPy attr.
+        # Using a lambda to only throw it away when it's wrong seems a problem
+        # as well.
+        config_method = None
+        if self._facade_version() < 13:
+            config_method = app_facade.SetApplicationsConfig
+        else:
+            config_method = app_facade.SetConfigs
+        return await config_method(args=[{
             "application": self.name,
             "config": config,
         }])