chore: upgrade dotenv and npm audit fix

The main reason for this PR is actually to support new features in dotenv
related to config via env vars.

see https://github.com/motdotla/dotenv#preload for examples of DOTENV_CONFIG_* env vars.

Note, this makes the use of the require('rc')('db-migrate') added via aef82c3 somewhat redundant,
since DOTENV_CONFIG_PATH is one of the env vars supported by dotenv.

Signed-off-by: Naseem Ullah <[email protected]>

Author: naseemkullah