Update java-firestore/owlbot.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: blakeli0

java-firestore/owlbot.py

@@ -48,10 +48,10 @@
     admin_version_path = "google-cloud-firestore-admin/src/main/java/com/google/cloud/firestore/v1/stub/Version.java"
     if os.path.exists(admin_version_path):
         target_path = "google-cloud-firestore-admin/src/main/java/com/google/cloud/firestore/v1/stub/FirestoreAdminVersion.java"
-        with open(admin_version_path, 'r') as f:
+        with open(admin_version_path, 'r', encoding='utf-8') as f:
             content = f.read()
         content = content.replace("class Version", "class FirestoreAdminVersion")
-        with open(target_path, 'w') as f:
+        with open(target_path, 'w', encoding='utf-8') as f:
             f.write(content)
         os.remove(admin_version_path)