bitbake-setup: sync layers to branch HEAD

Hi, I have a question regarding bitbake-setup.

In a *.conf.json file, I can configure bitbake-setup to use the latest commit
on a branch by setting `rev` to the same value as `branch`. For example:

"sources": {
    "openembedded-core": {
        "git-remote": {
            "uri": "https://git.openembedded.org/openembedded-core",
            "branch": "wrynose",
            "rev": "wrynose"
        }
    },
    ...
}

Over time, new commits are pushed to the upstream branch (wrynose). Is there a
way to sync my local checkout to the updated upstream branch without running
`git pull` manually for each layer? Originally, I assumed this would be done by
running `bitbake-setup update`, but no changes are detected, as the *.conf.json
file is still the same.

Regards, Christian