release: add semver based dependencies for versions that should work
release: add semver based dependencies for versions that should work

The only real requirement we have is that nix with the latest changes
that include the new ioctl code is present.  According to the semver
documentation `^0.3.6 := >=0.3.6 <0.4.0`, which could be correct.
When nix 0.4.0+ comes out, re-testing should take place to determine
if everything still works.

nastevens/rust-spidev,inre/rust-spidev