build: Don't branch or tag this in the named release

We only branch and tag top-level backend services,
frontend apps, and non-default Open edX plugins.
This, on the other hand, is a package that gets installed into
edx-platform. We shouldn't tag it, because its `release/ulmo` branch is not guaranteed to line up with the openedx-forum version installed by the
`release/ulmo` branch of edx-platform.

After merging, we should delete the `release/ulmo` tag.

Author: kdmccormick

catalog-info.yaml

@@ -7,7 +7,6 @@ metadata:
   name: "forum"
   description: "openedx forum app"
   annotations:
-    openedx.org/release: "master"
     openedx.org/arch-interest-groups: ""
 spec:
   owner: "group:wg-maintainers-forums"