Runtime versioner gets confused when auditing a merge commit

[John DiSanti]

The runtime-versioner audit command that gets run by pre-commit gets confused when auditing for a merge commit (for example, when merging main into a local feature branch).

For example, when merging main into one of my PR branches, running git merge --continue or git commit to complete the merge after resolving conflicts resulted in the following audit result:

     Running `/Users/jdisanti/src/smithy-rs/tools/target/debug/runtime-versioner audit`
2024-04-12T23:18:37.378299Z  WARN runtime_versioner::command::audit: there are newer releases since 'release-2024-04-02'
2024-04-12T23:18:43.916689Z  INFO runtime_versioner::command::audit: 'aws-config' changed and was version bumped from 1.1.10 to 1.2.1
2024-04-12T23:18:44.014764Z  INFO runtime_versioner::command::audit: 'aws-sigv4' changed and was version bumped from 1.2.0 to 1.2.1
2024-04-12T23:18:44.143456Z  INFO runtime_versioner::command::audit: 'aws-smithy-runtime' changed and was version bumped from 1.2.1 to 1.3.1
aws-credential-types was changed and version bumped, but the new version number (1.2.0) has already been published to crates.io. Choose a new version number.
aws-runtime was changed and version bumped, but the new version number (1.2.0) has already been published to crates.io. Choose a new version number.
aws-smithy-runtime-api was changed and version bumped, but the new version number (1.4.0) has already been published to crates.io. Choose a new version number.
aws-types was changed and version bumped, but the new version number (1.2.0) has already been published to crates.io. Choose a new version number.
Error: there are audit failures in the runtime crates

Looking at the diff, this audit result was clearly wrong. After completing the merge with git commit --no-verify, running runtime-versioner audit manually resulted in this correct audit:

❯ runtime-versioner audit
2024-04-12T23:20:45.723310Z  INFO runtime_versioner::command::audit: 'aws-config' changed and was version bumped from 1.2.0 to 1.2.1
2024-04-12T23:20:45.884663Z  INFO runtime_versioner::command::audit: 'aws-sigv4' changed and was version bumped from 1.2.0 to 1.2.1
2024-04-12T23:20:46.167308Z  INFO runtime_versioner::command::audit: 'aws-smithy-runtime' changed and was version bumped from 1.3.0 to 1.3.1
aws-smithy-runtime-api changed since release-2024-04-11 and requires a version bump
aws-types changed since release-2024-04-11 and requires a version bump
Error: there are audit failures in the runtime crates