Given RFC-761, unpin third-party packages, generating a new rubin-env and causing the newinstall docker containers to be updated, incidentally including Python 3.8.8.
Use Python 3.8.8 or later in the DM Docker image
New rubin-env has been merged; next is to update the versions in newinstall and lsstsw.
Mostly a one-character change in two repos, but I moved some lines around in newinstall.
Note: updating the lsst/lsst repo triggers a rebuild of the newinstall Docker container, which is then the basis for subsequent stack containers.