Hi Jeremy,
Maybe you should ask current PTL or any other current member of
that group to add you in https://launchpad.net/~murano-drivers/+members [...]
The only user who can add anyone to that team is Serg Melikyan (~smelikyan), so someone will need to reach out to him. When doing so, please also ask him to switch the owner of that group to OpenStack Administrators (~openstack-admins). Failing that, we'll need to get the Launchpad service administrators to help.
I managed to get in contact with Serg, and he's very helpfully added me as a member, and openstack-admins too. He said he can't make the openstack-admins account an admin until the account has accepted the membership invite. Jeremy, can you confirm once that's done, and I'll ask Serg to finish it off. Thanks!