Meltano

Is it possible to alias a property with a period in its name using `stream_maps`?

```      stream_maps:
        users:
          phoneNumberCountryCodeISO: _.get("itblInternal.phoneCountry")
          itblInternal.phoneCountry': __NULL__```
gives

```TypeError: unhashable type: 'dict'```
presumably because it is parsing the property definition as a dict i.e.

```{
  "itblInternal": {
    "phoneCountry": "__NULL__"
  }
}```
<https://github.com/meltano/sdk/blob/38a5ab9caea7b392931c3f2fd0df1aedf83f50e9/singer_sdk/mapper.py#L500>

You're probably running into <https://github.com/meltano/meltano/issues/8818>.

Though you may be able to get around it by using a json string env var