[ci] Review `cargo-semver-checks` Github Action workflows, find gaps related to feature resolution & re-exports of workspace dependencies

[jlizen]

Context: #1023

We had semver breakage in a lambda_http patch release due to its dependency on aws_lambda_events.

My understanding was that our CI should have failed this. We should find whether there is a gap in our CI setup, or a bug in cargo-semver-issues.