Since python 3.10 ssl.PROTOCOL_TLS has been deprecated. We are expected
to use ssl.PROTOCOL_TLS_CLIENT and ssl.PROTOCOL_TLS_SERVER depending on
how the sockets are to be used. Switch over to these new constants to
avoid the DeprecationWarning.
One thing to note is that PROTOCOL_TLS_CLIENT has default behaviors
around cert verification and hostname checking. Zuul is already
explicitly setting those options the way it wants to and I've left that
alone to avoid trouble if the defaults change later.
Finally, this doesn't fix the occurence of this error that happens
within kazoo. A separate PR has been made upstream to kazoo and this
should be fixed in the next kazoo release.
Change-Id: Ib41640f1d33d60503066464c8c98f865a74f003a