try to fix the umlaut encoding problem

src/run_modules/pre_processing.py

@@ -102,7 +102,7 @@ class PreProcessing(RunEnvironment):
         column_format[-1] = 'r'
         column_format = ''.join(column_format.tolist())
         df.to_latex(os.path.join(path, "test.tex"), na_rep='---', column_format=column_format)
-        df.to_markdown(open(os.path.join(path, "test.md"), "w"), tablefmt="github")
+        df.to_markdown(open(os.path.join(path, "test.md"), mode="w", encoding='utf-8'), tablefmt="github")
         df.drop(meta_data, axis=1).to_latex(os.path.join(path, "test_short.tex"), na_rep='---', column_format=column_format)
 
     def split_train_val_test(self) -> None: