Look for .env file in the caller directory first

[nothingface0]

This should fix some cases where the virtual environment used in NOT in the caller directory, but is somewhere else (e.g. ~/.virtualenvs).

Using load_dotenv without a path leads the python-dotenv package to look for .env in the directory hierarchy where the runregistry package is installed (in this example: ~/.virtualenvs).

We would, however, expect the .env file to be in the directory where the script using runregistry is.