Treat GitHub app and installation IDs as ints

Gidgethub treats app and installation IDs as str, but the GitHub
API appears to return int. Use int in GitHubAppClientFactory for
consistency with what GitHub returns, and convert them to str when
passing them to Gidgethub. Add a changelog entry and a note on the
class about this out of an abundance of caution.

changelog.d/20230918_114322_rra_DM_40744.md

@@ -0,0 +1,3 @@
+### Backwards-incompatible changes
+
+- `safir.github.GitHubAppClientFactory` now expects the application ID and installation ID (for `create_installation_client`) to be of type `int`, not `str`. This appears to match what GitHub's API returns, but not what Gidgethub expects. The ID is converted to a string when passing it to Gidgethub.

src/safir/github/_client.py

@@ -21,10 +21,16 @@ class GitHubAppClientFactory:
         from (e.g. ``lsst-sqre/times-square``).
     http_client
         The httpx client.
+
+    Notes
+    -----
+    Gidgethub treats the application ID and installation ID as strings, but
+    GitHub's API appears to return them as integers. This class expects them
+    to be integers and converts them to strings when calling Gidgethub.
     """
 
     def __init__(
-        self, *, id: str, key: str, name: str, http_client: httpx.AsyncClient
+        self, *, id: int, key: str, name: str, http_client: httpx.AsyncClient
     ) -> None:
         self.app_id = id
         self.app_key = key
@@ -43,7 +49,7 @@ def get_app_jwt(self) -> str:
             The JWT token.
         """
         return gidgethub.apps.get_jwt(
-            app_id=self.app_id, private_key=self.app_key
+            app_id=str(self.app_id), private_key=self.app_key
         )
 
     def _create_client(self, *, oauth_token: str | None = None) -> GitHubAPI:
@@ -72,7 +78,7 @@ def create_app_client(self) -> GitHubAPI:
         return self._create_client(oauth_token=self.get_app_jwt())
 
     async def create_installation_client(
-        self, installation_id: str
+        self, installation_id: int
     ) -> GitHubAPI:
         """Create a client authenticated as an installation of the GitHub App
         for a specific repository or organization.
@@ -93,8 +99,8 @@ async def create_installation_client(
         anon_client = self.create_anonymous_client()
         token_info = await gidgethub.apps.get_installation_access_token(
             anon_client,
-            installation_id=installation_id,
-            app_id=self.app_id,
+            installation_id=str(installation_id),
+            app_id=str(self.app_id),
             private_key=self.app_key,
         )
         return self._create_client(oauth_token=token_info["token"])