Swap out ruamel.yaml with pyyaml

mypy was unhappy with the import

code_submitter/auth.py

@@ -5,8 +5,8 @@
 from typing import cast, Dict, List, Tuple, Optional, Sequence
 from typing_extensions import TypedDict
 
+import yaml
 import httpx
-from ruamel.yaml import YAML
 from starlette.requests import HTTPConnection
 from starlette.responses import Response
 from starlette.applications import Starlette
@@ -223,7 +223,7 @@ def __init__(
         path: str,
     ) -> None:
         with open(path) as f:
-            self.credentials = cast(Dict[str, str], YAML(typ="safe").load(f))
+            self.credentials = cast(Dict[str, str], yaml.safe_load(f))
 
     def get_scopes(self, username: str) -> List[str]:
         scopes = ['authenticated']

requirements.in

@@ -5,4 +5,4 @@ databases[sqlite]
 sqlalchemy
 alembic
 httpx
-ruamel.yaml
+pyyaml

requirements.txt

@@ -26,9 +26,8 @@ markupsafe==1.1.1         # via jinja2, mako
 python-dateutil==2.8.1    # via alembic
 python-editor==1.0.4      # via alembic
 python-multipart==0.0.5   # via -r requirements.in
+pyyaml==5.3.1             # via -r requirements.in
 rfc3986==1.4.0            # via httpx
-ruamel.yaml.clib==0.2.2   # via ruamel.yaml
-ruamel.yaml==0.16.12      # via -r requirements.in
 six==1.15.0               # via python-dateutil, python-multipart
 sniffio==1.1.0            # via httpcore, httpx
 sqlalchemy==1.3.18        # via -r requirements.in, alembic, databases