Stop uploading -py3 docker images (#8056)

.circleci/config.yml

@@ -4,18 +4,16 @@ jobs:
     machine: true
     steps:
       - checkout
-      - run: docker build -f docker/Dockerfile --label gitsha1=${CIRCLE_SHA1} -t matrixdotorg/synapse:${CIRCLE_TAG} -t matrixdotorg/synapse:${CIRCLE_TAG}-py3 .
+      - run: docker build -f docker/Dockerfile --label gitsha1=${CIRCLE_SHA1} -t matrixdotorg/synapse:${CIRCLE_TAG} .
       - run: docker login --username $DOCKER_HUB_USERNAME --password $DOCKER_HUB_PASSWORD
       - run: docker push matrixdotorg/synapse:${CIRCLE_TAG}
-      - run: docker push matrixdotorg/synapse:${CIRCLE_TAG}-py3
   dockerhubuploadlatest:
     machine: true
     steps:
       - checkout
-      - run: docker build -f docker/Dockerfile --label gitsha1=${CIRCLE_SHA1} -t matrixdotorg/synapse:latest -t matrixdotorg/synapse:latest-py3 .
+      - run: docker build -f docker/Dockerfile --label gitsha1=${CIRCLE_SHA1} -t matrixdotorg/synapse:latest .
       - run: docker login --username $DOCKER_HUB_USERNAME --password $DOCKER_HUB_PASSWORD
       - run: docker push matrixdotorg/synapse:latest
-      - run: docker push matrixdotorg/synapse:latest-py3
 
 workflows:
   version: 2

changelog.d/8056.docker

@@ -0,0 +1 @@
+We no longer publish Docker images with the `-py3` tag suffix, as announced at https://github.com/matrix-org/synapse/blob/develop/UPGRADE.rst#upgrading-to-v1180.