remove github ref type checking on push

[cyinma]

fixes #26

This remove the checking of GITHUB_REF_TYPE environment variable equals to branch in the action, which was added to support draft. Also updated the readme example which is more aligned with the flow we suggest.

My original thought for this fix was to put the checking inside the block of if [ "${DRAFT}" == "true" ]; then so that its only check when it is expected to be a draft, but after thinking about this more it doesn't seems to be a necessary check for draft neither (or at least not something we should block for the user), as user might also want to only push as draft when pushing a git tag, so decided to just remove the GITHUB_REF_TYPE checking.

tested with an action condition of

on:
  push:
    tags:
      - push-to-bsr

and its working as expected (push to bsr main when adding a tag push-to-bsr)