Example of working from pull request

[kaihendry]

I've noticed this action doesn't work off the "main" branch very well.

We have a Pull Request review flow and I tried:

with:
          main-branch-name: ${{ github.ref_name }}

Though it errored with:

No explicit --head argument provided, but found environment variable NX_HEAD so using its value as the affected head

I re-read https://github.com/nrwl/nx-set-shas#problem and am I right to assume it's a solved problem with a PR workflow? If it is, why mention it in the README other to confuse dopes like me. =)

[mandarini]

Hi there @kaihendry ! Thanks for filing this issue! Do you think this is just a documentation issue, and can be fixed by rewording the readme? What do you think would sound less confusing?