For release-type go projects version-file is ignored.

Currently for a configuration like this:

```json
{
  "release-type": "go",
  "packages": {
    ".": {
      "version-file": "internal/version/version.go",
      "extra-files": ["internal/version/version.go"]
    }
  },
  "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json"
}
```

The version increase automation does nothing. 