bindings: make s2n-tls-sys crate version match C release

[camshaft]

Problem:

Only one version of s2n-tls-sys crate can exist in a single workspace or binary (see #4296).

Solution:

One way to improve this issue is to bump s2n-tls-sys to a major version and have it track the same version as the C releases. This will make it easier to know which C build is consumed in any given application. It will also allow for minor bumps in the Rust bindings, without causing conflicting dependency requirements in downstream applications.

[maddeleine]

Change also requires reviewing and updating our release process.