Server communication: passing environment variables

This recipe shows how to pass environment variables to your tests

See package.json file which runs Cypress with environment variables set. The variables that start with CYPRESS_ are extracted automatically. Other variables are copied from process.env in the script cypress/plugins/index.js
Additional variables can be passed via env object in cypress.json
Extract any other variable from process.env using cypress/plugins/index.js callback.
Uses dotenv package to read the .env file in the plugins file