Update headers type

docs/docs/concepts/auth.md

@@ -112,7 +112,7 @@ auth = Auth()
 @auth.authenticate
 async def authenticate(headers: dict) -> Auth.types.MinimalUserDict:
     # Validate credentials (e.g., API key, JWT token)
-    api_key = headers.get("x-api-key")
+    api_key = headers.get(b"x-api-key")
     if not api_key or not is_valid_key(api_key):
         raise Auth.exceptions.HTTPException(
             status_code=401,

docs/docs/how-tos/auth/custom_auth.md

@@ -43,7 +43,7 @@ To leverage custom authentication and access user-level metadata in your deploym
 
     @auth.authenticate # (1)!
     async def authenticate(headers: dict) -> Auth.types.MinimalUserDict:
-        api_key = headers.get("x-api-key")
+        api_key = headers.get(b"x-api-key")
         if not api_key or not is_valid_key(api_key):
             raise Auth.exceptions.HTTPException(status_code=401, detail="Invalid API key")