Add default RegionScope for SigV4a signers

[dagnir]

Motivation and Context

Support certain customer use cases where setting a custom region scope is necessary.

Modifications

This commit adds support for setting the default RegionScope used by the Sigv4a
signer implementations. If the region scope to use is not supplied to the
signing methods, the signers will default to this scope first and then the
normal signing region.

Testing

New unit tests.

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist

• I have read the CONTRIBUTING document
• Local run of mvn install succeeds
• My code follows the code style of this project
• My change requires a change to the Javadoc documentation
• I have updated the Javadoc documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed
• I have added a changelog entry. Adding a new entry must be accomplished by running the scripts/new-change script and following the instructions. Commit the new file created by the script in .changes/next-release with your changes.
• My change is to implement 1.11 parity feature and I have updated LaunchChangelog

License

• I confirm that this pull request can be released under the Apache 2 license

[sonarqubecloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
6 Code Smells

27.4% Coverage
9.9% Duplication