chore(release): specify utf-8 encoding for file operations

Author: rickeylev

tests/tools/private/release/promote_rc_test.py

@@ -83,7 +83,7 @@ def test_promote_rc_writes_github_output(self):
         # Assert
         self.assertEqual(result, 0)
         self.assertTrue(os.path.exists(github_output_path))
-        content = Path(github_output_path).read_text()
+        content = Path(github_output_path).read_text(encoding="utf-8")
         self.assertEqual(content, "version=2.0.0\n")
 
     def test_promote_rc_resolve_issue_success(self):

tools/private/release/promote_rc.py

@@ -158,7 +158,7 @@ def run(self) -> int:
         self.git.push(args.remote, version)
 
         if github_output := os.environ.get("GITHUB_OUTPUT"):
-            with open(github_output, "a") as f:
+            with open(github_output, "a", encoding="utf-8") as f:
                 f.write(f"version={version}\n")
 
         print(f"Updating tracking issue #{issue_num} checklist...")