Pact Foundation

But the plugin still cannot spawn child process.

That looks like the test can't start the plugin. Can you try start the same docker container and try run `pact-protobuf-plugin`

I forgot to add
```"hostToBindTo": "127.0.0.1"```
into 'pact-plugin.json`
{
  "manifestVersion": 1,
  "pluginInterfaceVersion": 1,
  "name": "protobuf",
  "version": "0.1.8",
  "executableType": "exec",
  "entryPoint": "pact-protobuf-plugin",
  "pluginConfig": {
    "protocVersion": "3.19.1",
    "downloadUrl": "<https://github.com/protocolbuffers/protobuf/releases/download>",
    "hostToBindTo": "127.0.0.1"
  }
}