Just cache builds on mybinder

.github/workflows/binder.yaml

@@ -1,15 +1,12 @@
-name: Build Notebook Container
-on: [push] # May want to trigger this Action on other things than a push
+name: Binder
+on: [push]
+
 jobs:
-  build:
+  Create-MyBinderOrg-Cache:
     runs-on: ubuntu-latest
     steps:
-      - name: checkout files in repo
-        uses: actions/checkout@master
-
-      - name: update jupyter dependencies with repo2docker
-        uses: machine-learning-apps/repo2docker-action@master
+      - name: cache binder build on mybinder.org
+        uses: jupyterhub/repo2docker-action@master
         with:
-          DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
-          DOCKER_PASSWORD: ${{ secrets.DOCKER_PASSWORD }}
-          BINDER_CACHE: true
+          NO_PUSH: true
+          MYBINDERORG_TAG: ${{ github.event.ref }} # This builds the container on mybinder.org with the branch that was pushed on.