master-opencm3-projects: Build from gitea, not git

git.osmocom.org is a mirror of gitea.osmocom.org, let's build from
the actual master repo, not from the (possibly slightly outdated) mirror

Change-Id: I12d090a9ee7fde09892567ada739826484a4a35b

jobs/master-builds.yml

@@ -376,6 +376,7 @@
           cmd: '{docker_run} {docker_img} /build/contrib/jenkins.sh --publish'
           email: gerrit-log@lists.osmocom.org laforge@gnumonks.org kredon@sysmocom.de
       - osmo-opencm3-projects:
+          git_base_url: https://gitea.osmocom.org/electronics
           docker_img: '$USER/debian-bullseye-jenkins'
           cmd: '{docker_run} {docker_img} /build/contrib/jenkins.sh --publish'
           email: gerrit-log@lists.osmocom.org laforge@gnumonks.org kredon@sysmocom.de