centos-8 fails to update: ModuleNotFoundError: No module named '_contextvars'

[Rob Townley]

I certainly may not have run the qubesctl command correctly, but the gui based update utility also fails.  I had changed the default disposable template to fedora-34-qubes-core.  Does it need to be a centos-8 template to work?  

[root@dom0 ~]# qubesctl --skip-dom0 --targets=centos-8 --show-output --force-color state.sls update.qubes-vm
centos-8:
  centos-8:
      ----------
      _error:
          Failed to return clean data
      retcode:
          1
      stderr:
          Traceback (most recent call last):
            File "/var/tmp/.root_dd8a91_salt/pyall/salt/loader_context.py", line 10, in <module>
              import _contextvars as contextvars
          ModuleNotFoundError: No module named '_contextvars'
         
          During handling of the above exception, another exception occurred:
         
          Traceback (most recent call last):
            File "/var/tmp/.root_dd8a91_salt/salt-call", line 27, in <module>
              salt_call()
            File "/var/tmp/.root_dd8a91_salt/pyall/salt/scripts.py", line 437, in salt_call
              import salt.cli.call
            File "/var/tmp/.root_dd8a91_salt/pyall/salt/cli/call.py", line 6, in <module>
              import salt.cli.caller
            File "/var/tmp/.root_dd8a91_salt/pyall/salt/cli/caller.py", line 14, in <module>
              import salt.loader
            File "/var/tmp/.root_dd8a91_salt/pyall/salt/loader.py", line 29, in <module>
              import salt.loader_context
            File "/var/tmp/.root_dd8a91_salt/pyall/salt/loader_context.py", line 13, in <module>
              import contextvars
            File "/var/tmp/.root_dd8a91_salt/py3/contextvars.py", line 1, in <module>
              from _contextvars import Context, ContextVar, Token, copy_context
          ModuleNotFoundError: No module named '_contextvars'
      stdout:
[root@dom0 ~]#

[Rob Townley]

The only thing out of the ordinary is I have an outdated is the DisposableVM  Template.