* cli: add --target-version CLI flags for migrate run/revert
* cli: fix broken test
* cli: test harness for `sqlx migrate` along with --target-version tests
* cli: Fail if version supplied to run/revert is too old/new
After some discussion with my coworkers, we thought about the behavior a bit more:
The behavior is now that for a run, if the provided version is too old, the CLI
will return with failure rather than being a no-op. This gives feedback to the
operator instead of being quiet.
It is still valid to up/downgrade to the latest version, this will still be a no-op
to allow for idempotency.
