Merge pull request #3998 from matrix-org/michaelkaye/build_docker_images_of_rc_tags

Docker build all tags starting vX.Y.Z, including release candidates

.circleci/config.yml

@@ -156,7 +156,7 @@ workflows:
       - dockerhubuploadrelease:
           filters:
             tags:
-              only: /^v[0-9].[0-9]+.[0-9]+(.[0-9]+)?/
+              only: /v[0-9].[0-9]+.[0-9]+.*/
             branches:
               ignore: /.*/
       - dockerhubuploadlatest: