Add testing against Rust beta
Add testing against Rust beta

We might discover something that we, and the Rust team, might be glad of
this way.

Signed-off-by: mulhern <7b51bcf507bcd7afb72bf8663752c0ddbeb517f6@redhat.com>

trgill/stratisd,stratis-storage/stratisd,stratis-storage/stratisd,trgill/stratisd,stratis-storage/stratisd