Fix regression against older servers (#868)

* Fix regression against older servers

* Update CHANGELOG

CHANGELOG.md

@@ -11,6 +11,9 @@ Write the date in place of the "Unreleased" in the case a new version is release
   classmethods for instantiation from files and registered Tiled nodes, respectively.
 - Refactor CSVAdapter to allow pd.read_csv kwargs
 - Removed `tiled.adapters.zarr.read_zarr` utility function.
+- Server declares authentication provider modes are `external` or `internal`. The
+  latter was renamed from `password`. Client accepts either `internal` or `password`
+  for backward-compatibility with older servers.
 
 ### Added
 

tiled/schemas.py

@@ -1,6 +1,6 @@
 from typing import Any, Dict, List, Literal, Optional
 
-from pydantic import BaseModel
+from pydantic import BaseModel, field_validator
 
 
 class AboutAuthenticationProvider(BaseModel):
@@ -9,6 +9,13 @@ class AboutAuthenticationProvider(BaseModel):
     links: Dict[str, str]
     confirmation_message: Optional[str] = None
 
+    @field_validator("mode", mode="before")
+    @classmethod
+    def accept_mode_password_as_backcompat_alias_for_internal(cls, value: Any) -> Any:
+        if isinstance(value, str) and value == "password":
+            value = "internal"
+        return value
+
 
 class AboutAuthenticationLinks(BaseModel):
     whoami: str