fix: allow Protobuf 7.x (googleapis#16532)

Fixes googleapis#16526

See related PR
googleapis#16102. Note:
We're still waiting on a fix for
grpc/grpc#41933

Author: parthea

packages/google-api-core/pyproject.toml

@@ -45,7 +45,7 @@ classifiers = [
 ]
 dependencies = [
   "googleapis-common-protos >= 1.63.2, < 2.0.0",
-  "protobuf >= 4.25.8, < 7.0.0",
+  "protobuf >= 4.25.8, < 8.0.0",
   "proto-plus >= 1.22.3, < 2.0.0",
   "proto-plus >= 1.25.0, < 2.0.0; python_version >= '3.13'",
   "google-auth >= 2.14.1, < 3.0.0",