nbgitpuller cannot pull from github to docker hub image

[rdmolony]

Describe the bug
I'm currently using an environment repo and a content repo as per this discussion and tried your docker hub action to save the environment repo to docker hub.

When running https://mybinder.org/v2/gh/codema-dev/projects-sandbox/main?urlpath=git-pull%3Frepo%3Dhttps%253A%252F%252Fgithub.com%252Fcodema-dev%252Fprojects%26urlpath%3Dlab%252Ftree%252Fprojects%252Fbinder.ipynb%26branch%3Dmain pulling the environment image from docker hub mybinder.org build failed with

(see here for more information)

I've reverted back to code used from here before pushing to docker hub and once again it runs fine - https://github.com/codema-dev/projects

To Reproduce
Steps to reproduce the behavior:

1. Push an environment repo to docker hub by saving this action in .github/workflows.binder.yaml

name: Binder
on: [push]

jobs:
  binder:
    runs-on: ubuntu-latest
    environment: docker
    steps:
    - name: Checkout Code
      uses: actions/checkout@v2
      with:
        ref: ${{ github.event.pull_request.head.sha }}

    - name: update jupyter dependencies with repo2docker
      uses: jupyterhub/repo2docker-action@master
      with:
        DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
        DOCKER_PASSWORD: ${{ secrets.DOCKER_PASSWORD }}
        BINDER_CACHE: true
        PUBLIC_REGISTRY_CHECK: true

2. Generate a binder link on the environment repo and on the content repo here
3. Click the binder link

Expected behavior
nbgitpuller pulls from the content repo as expected

---

Thanks a lot for all your work on this action, Binder has been a life saver in opening up our work to the wider public!

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[manics]

https://mybinder.org/v2/gh/codema-dev/projects-sandbox/main?urlpath=git-pull%3Frepo%3Dhttps%253A%252F%252Fgithub.com%252Fcodema-dev%252Fprojects%26urlpath%3Dlab%252Ftree%252Fprojects%252Fbinder.ipynb%26branch%3Dmain

That links loads fine for me.

[rdmolony]

Thanks a lot for getting back to me @manics! The main branch works right now as I reverted to a commit without a binder/Dockerfile linking to docker hub - I made a new branch off the failing commit containing the binder/Dockerfile see -
https://mybinder.org/v2/gh/codema-dev/projects-sandbox/revert-to-push-to-docker-hub?urlpath=git-pull%3Frepo%3Dhttps%253A%252F%252Fgithub.com%252Fcodema-dev%252Fprojects%26urlpath%3Dlab%252Ftree%252Fprojects%252Fbinder.ipynb%26branch%3Dmain

(using the amazing nbgitpuller link to generate it)