Update environment-variables.md

[cirex-web]

Would've saved me 15 minutes :P

[garronej]

Hey @cirex-web,

Thank you, although this command is supposed to be like an internal command for thoses developping keycloakify plugins.
You shouldn't have to run it manually.
It's supposed to be run internally whenever you have the dev server running (yarn dev) or storybook running (yarn storybook) or whenever you build (yarn build-keycloak-theme).
Is there a problem with that?

Anyway I agree that something need to be added here! It's just that I'm not very confortable exposing pepole with a new command.

[cirex-web]

hm... kc.gen.tsx didn't update when storybook was running - it only updated when I restarted storybook