fix: require proto-plus >= 1.25.0 for Python 3.13 (#740)

Author: parthea

setup.py

@@ -31,7 +31,8 @@
 dependencies = [
     "googleapis-common-protos >= 1.56.2, < 2.0.dev0",
     "protobuf>=3.19.5,<6.0.0.dev0,!=3.20.0,!=3.20.1,!=4.21.0,!=4.21.1,!=4.21.2,!=4.21.3,!=4.21.4,!=4.21.5",
-    "proto-plus >= 1.22.3, <2.0.0dev",
+    "proto-plus >= 1.22.3, < 2.0.0dev",
+    "proto-plus >= 1.25.0, < 2.0.0dev; python_version >= '3.13'",
     "google-auth >= 2.14.1, < 3.0.dev0",
     "requests >= 2.18.0, < 3.0.0.dev0",
 ]