[ci] mark github.Repository as typechecking (#58582)

so that importing test.py does not always import github

github repo imports jwt, which then imports cryptography and can lead to
issues on windows.

Signed-off-by: Lonnie Liu <[email protected]>

Author: aslonnie

release/ray_release/test.py

@@ -8,12 +8,14 @@
 import time
 from dataclasses import dataclass
 from itertools import chain
-from typing import Awaitable, Dict, List, Optional, Set
+from typing import TYPE_CHECKING, Awaitable, Dict, List, Optional, Set
 
 import aioboto3
 import boto3
 from botocore.exceptions import ClientError
-from github import Repository
+
+if TYPE_CHECKING:
+    from github import Repository
 
 from ray_release.aws import s3_put_rayci_test_data
 from ray_release.configs.global_config import get_global_config
@@ -355,7 +357,7 @@ def _get_test_targets_per_file(
         except subprocess.CalledProcessError:
             return set()
 
-    def is_jailed_with_open_issue(self, ray_github: Repository) -> bool:
+    def is_jailed_with_open_issue(self, ray_github: "Repository") -> bool:
         """
         Returns whether this test is jailed with open issue.
         """