feat: save config as json (#483)

Pickled `FullConfigSchema`s will break when loading if the signature of
`FullConfigSchema` has changed, since `allow_extra` is false. As a
backup, we now save as json as well.

.gitignore

@@ -129,4 +129,5 @@ package.json
 *.csv
 
 evaluation_results
-*.pqt
+*.pqt
+tests/test_eval_results

src/psycop_model_training/training_output/artifact_saver/to_disk.py

@@ -1,3 +1,4 @@
+import json
 import logging
 from pathlib import Path
 from typing import Any, Optional, Union
@@ -82,6 +83,10 @@ def save(
         if cfg is not None:
             dump_to_pickle(cfg, self.dir_path / "cfg.pkl")
 
+            with (self.dir_path / "cfg.json").open(mode="w") as f:
+                cfg_dict = cfg.json()
+                json.dump(cfg_dict, f)
+
         if pipe_metadata is not None:
             dump_to_pickle(pipe_metadata, self.dir_path / "pipe_metadata.pkl")