[semver:patch] Fix setting variables in bash

[a14m]

Fixes #13

[tanansatpal]

Can we have this change merged guys? It is useless now without this change

[a14m]

You can use this fork https://circleci.com/orbs/registry/orb/sapera/heroku-orb
It's based on this #12
but uses ref key instead of branch to work with both tags/branches... we've been using it for production (for short time now) and it's been working fine,
I've cleaned the git history, but you can check the difference between the fork and the 1.1.1 version here:
infographicsgroup@ea05c65

[gmemstr]

LGTM, waiting for tests to pass before merging