Update your .circleci/config.yml files to add Docker Hub authentication.

config.yaml.diff

version: 2.1

+ # Docker Hub authentication managed by the shared `dockerhub-shared` context.
+ docker-auth: &docker-auth
+  auth:
+    username: $DOCKERHUB_USERNAME
+    password: $DOCKERHUB_ACCESS_TOKEN

jobs:
  test:
    docker:
      - image: circleci/whatever
+       <<: *docker-auth
    steps:
      - checkout
      - ...
  deploy:
    docker:
      - image: anyorg/whatever
+       <<: *docker-auth
    steps:
      - checkout
      - ...
      
workflows:
  version: 2
  workflow:
    jobs:
      - test:
+         context: dockerhub-shared
      - deploy:
          context: 
+           - dockerhub-shared
            - some-other-context-if-necessary