chore(deps): update dependency @grpc/proto-loader to ^0.8.0

Author: renovate-bot

package.json

@@ -36,7 +36,7 @@
     "protobufjs": "7.4.0"
   },
   "devDependencies": {
-    "@grpc/proto-loader": "^0.7.0",
+    "@grpc/proto-loader": "^0.8.0",
     "@google-cloud/spanner": "^6.0.0",
     "c8": "^7.7.2",
     "google-auth-library": "^8.0.0",