If a `.env` file is found and loaded, but the `dotenv-load` setting hasn't been explicitly
set to true, print a warning to stderr. In approximately six months, `dotenv-load` will
change from defaulting to true to defaulting to false, which will be a potentially breaking
change in behavior for justfiles which elicit this warning.
See this issue for more details:
https://github.com/casey/just/issues/469
If an environment variable exists with the same key as a variable from a
`.env` file, skip the variable from the `.env` file in favor fo the key
from the environment.
Eventually, there will probably be a `crate` visibility specifier that
does the same thing as `pub(crate)`. This commit replaces `pub` with
`pub(crate)`, so when `crate` is available we can easily switch to it.
