chore: add compatibility for Protobuf v4 (#550)

Author: bshaffer

composer.json

@@ -8,9 +8,9 @@
     "require": {
         "php": "^8.0",
         "google/auth": "^1.34.0",
-        "google/grpc-gcp": "^0.3",
+        "google/grpc-gcp": "^0.4",
         "grpc/grpc": "^1.13",
-        "google/protobuf": "^3.22",
+        "google/protobuf": "^v3.25.3||^4.26.1",
         "guzzlehttp/promises": "^2.0",
         "guzzlehttp/psr7": "^2.0",
         "google/common-protos": "^4.4",