@Jura was thinking about getting Circle CI running too.
The answer is apparently yes: https://support.circleci.com/hc/en-us/articles/115015481128-Scheduling-jobs-cron-for-builds-
Also:
I guess if the default is to build when committing to master, then just build in a dev branch, and merge it to master to trigger the build. Not sure; have not tested yet.