I don't think providing an example .env file is worth the clutter. also want to keep the faq very short and simple to parse

maybe we change

spice looks for a Dune API key in the DUNE_API_KEY environment variable.

to

Set your API key using one of these approaches:

1. specify key across all sessions: set the DUNE_API_KEY environment variable (e.g. write export DUNE_API_KEY=your-api-key in your ~/.bash_profile)
2. specify key for single session: set the 'DUNE_API_KEY' entry in os.environ (e.g. os.environ['DUNE_API_KEY'] = 'your-api-key)
3. specify key per request: use the api_key function variable in python (query(api_key='your-api-key', ...)) or the --api-key argument from the cli (spice --api-key your-api-key ...)

sure thats a good idea. Updated readme accordingly