Fix two small bugs (#72)

1) a `PosixPath` was just as a parameter where a `str` was expected
2) the headline in the RL jupyter evaluation notebook was not updated to
the new reward functions

Author: nquetschlich

notebooks/rl/evaluation.ipynb

@@ -386,7 +386,7 @@
    "id": "5cd42294",
    "metadata": {},
    "source": [
-    "# 3x3 Matrix With Mean Result and RL Optimization Criterion"
+    "# 4x4 Matrix With Mean Results and RL Optimization Criterion Comparison"
    ]
   },
   {

src/mqt/predictor/rl/Predictor.py

@@ -87,7 +87,7 @@ def evaluate_all_sample_circuits(self) -> None:
         res_csv = []
 
         results = Parallel(n_jobs=-1, verbose=3, backend="threading")(
-            delayed(self.evaluate_sample_circuit)(file)
+            delayed(self.evaluate_sample_circuit)(str(file))
             for file in list(rl.helper.get_path_training_circuits().glob("*.qasm"))
         )
         res_csv.append(list(results[0].keys()))