Add tool to simulate a release dry run (#3327)

## Motivation and Context
As we discovered in #3318, it's possible to cause unexpected breakage by
releasing runtime crates.
 
This tool automates setting up `aws-sdk-rust` (and manually, you can
copy the patches into `~/.cargo/config.toml` for your entire system), to
simulate the release of new runtime crates.

<img width="1518" alt="Screenshot 2023-12-15 at 12 58 41 PM"
src="https://github.com/smithy-lang/smithy-rs/assets/492903/59d6cb5c-d39c-4e42-98e2-6858d0884449">


### Testing
With this tool (and a small hack—I had to simulate releasing 1.1.100 so
that the versions became the latest), I correctly caught the breaking
changes from the previous release.


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