Tell CircleCI to build Docker images from `main` (#9906)

The `only` field takes a string or list of strings per the Circle docs:
https://circleci.com/docs/2.0/configuration-reference/#branches

Signed-off-by: Dan Callahan <danc@element.io>

2 files changed, 2 insertions, 1 deletions

diff --git a/.circleci/config.yml b/.circleci/config.yml

index 1ac48a71ba..cf1989eff9 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -41,7 +41,7 @@ workflows:
       - dockerhubuploadlatest:
           filters:
             branches:
-              only: master
+              only: [ master, main ]
 
 commands:
   docker_prepare:
diff --git a/changelog.d/9906.misc b/changelog.d/9906.misc
new file mode 100644

index 0000000000..667d51a4c0
--- /dev/null
+++ b/changelog.d/9906.misc
@@ -0,0 +1 @@
+Tell CircleCI to build Docker images from `main` branch.