Use quay.io as source of docker images

While we do have 'sponsored OSS' status on dockerhub,
@choldgraf (whose credit card is apparently tied to the
dockerhub jupyterhub account) just got a surprise multi hundred
dollar bill for that organization! While I'm sure this is a
mistake and can be corrected, it's IMO enough incentive for us
to move away for real.

.github/workflows/publish.yml

@@ -108,7 +108,7 @@ jobs:
         #    https://github.com/jupyterhub/zero-to-jupyterhub-k8s/settings/secrets/actions
         if: steps.publishing.outputs.publishing
         run: |
-          docker login -u "${{ secrets.DOCKER_USERNAME }}" -p "${{ secrets.DOCKER_PASSWORD }}"
+          docker login -u "${{ secrets.QUAY_USERNAME }}" -p "${{ secrets.QUAY_PASSWORD }}" quay.io
 
       - name: Configure a git user
         # Having a user.email and user.name configured with git is required to

chartpress.yaml

@@ -12,7 +12,7 @@ charts:
   - name: jupyterhub
     # Dev: imagePrefix can be useful to override if you want to trial something
     #      locally developed in a remote k8s cluster.
-    imagePrefix: jupyterhub/k8s-
+    imagePrefix: quay.io/jupyterhub/k8s-
     # baseVersion should be a -0.dev suffixed version, where the version should
     # be the next major, minor, or patch version depending on what we have
     # merged so far into the main branch. If for example we have merged a

jupyterhub/values.yaml

@@ -83,7 +83,7 @@ hub:
   extraVolumes: []
   extraVolumeMounts: []
   image:
-    name: jupyterhub/k8s-hub
+    name: quay.io/jupyterhub/k8s-hub
     tag: "set-by-chartpress"
     pullPolicy:
     pullSecrets: []
@@ -201,7 +201,7 @@ proxy:
       runAsGroup: 65534 # nobody group
       allowPrivilegeEscalation: false
     image:
-      name: jupyterhub/configurable-http-proxy
+      name: quay.io/jupyterhub/configurable-http-proxy
       # tag is automatically bumped to new patch versions by the
       # watch-dependencies.yaml workflow.
       #
@@ -304,7 +304,7 @@ proxy:
       runAsGroup: 65534 # nobody group
       allowPrivilegeEscalation: false
     image:
-      name: jupyterhub/k8s-secret-sync
+      name: quay.io/jupyterhub/k8s-secret-sync
       tag: "set-by-chartpress"
       pullPolicy:
       pullSecrets: []
@@ -396,7 +396,7 @@ singleuser:
       volumeNameTemplate: volume-{username}{servername}
       storageAccessModes: [ReadWriteOnce]
   image:
-    name: jupyterhub/k8s-singleuser-sample
+    name: quay.io/jupyterhub/k8s-singleuser-sample
     tag: "set-by-chartpress"
     pullPolicy:
     pullSecrets: []
@@ -605,7 +605,7 @@ prePuller:
     pullOnlyOnChanges: true
     # image and the configuration below relates to the hook-image-awaiter Job
     image:
-      name: jupyterhub/k8s-image-awaiter
+      name: quay.io/jupyterhub/k8s-image-awaiter
       tag: "set-by-chartpress"
       pullPolicy:
       pullSecrets: []