Use orm.Dict.get_dict() to get the Python dictionary (#211)

In earlier versions of AiiDA (I guess <2.5) the `get()` method is not yet implemented
for the `orm.Dict` object. To support a wider range of AiiDA versions, we convert an
`omr.Dict` to the regular Python dictionary.

aiida_cp2k/workchains/base.py

@@ -65,7 +65,7 @@ def results(self):
         trajectories = self._collect_all_trajetories()
         if trajectories:
             self.report("Work chain completed successfully, collecting all trajectories")
-            if self.ctx.inputs.parameters.get("GLOBAL", {}).get("RUN_TYPE") == "GEO_OPT":
+            if self.ctx.inputs.parameters.get_dict().get("GLOBAL", {}).get("RUN_TYPE") == "GEO_OPT":
                 output_trajectory = utils.merge_trajectory_data_non_unique(*trajectories)
             else:
                 output_trajectory = utils.merge_trajectory_data_unique(*trajectories)