disable auth if env variables are not set

app.py

@@ -21,7 +21,7 @@ async def basic_auth(request: Request, call_next):
     auth = request.headers.get("Authorization")
     expected = "Basic " + base64.b64encode(f"{USERNAME}:{PASSWORD}".encode()).decode()
 
-    if auth != expected:
+    if USERNAME and PASSWORD and auth != expected:
         return Response(
             status_code=status.HTTP_401_UNAUTHORIZED,
             headers={"WWW-Authenticate": "Basic"},