[BUG] "Invalid private key" for ^1.20.0 when DOTENVX_PRO_USER set

```shell
rm .env*
touch .env
dotenvx set HELLO World
```

Exits with `Invalid private key` message and `0` status for `^1.20.0`,
when file `$HOME/.config/dotenvx/.env` contains `DOTENVX_PRO_USER`.
