Wrong charset, conversion from `utf-7' to `utf-8'

On php:7.2-cli-alpine

```bash
# php -d error_reporting=E_ALL -r 'var_dump(iconv("utf-7", "utf-8", "test"));'

Notice: iconv(): Wrong charset, conversion from `utf-7' to `utf-8'
is not allowed in Command line code on line 1
```