handle git submodules

templates/buildbot/master.cfg.j2

@@ -117,6 +117,7 @@ for builders_config_file_path in builders_config_file_paths:
           branch=repo["branch"],
           workdir=repo['workdir'],
           progress=True,
+          submodules=True,
         ))
       elif repo['type'] == 'gitea':
         factory.addStep(steps.Gitea(
@@ -125,6 +126,7 @@ for builders_config_file_path in builders_config_file_paths:
           branch=repo["branch"],
           workdir=repo['workdir'],
           progress=True,
+          submodules=True,
         ))
 
       for cmd in builder_config['shell_commands']: