Bump aws-sdk from 2.1555.0 to 2.1556.0

Bumps [aws-sdk](https://github.com/aws/aws-sdk-js) from 2.1555.0 to 2.1556.0.
- [Release notes](https://github.com/aws/aws-sdk-js/releases)
- [Commits](aws/aws-sdk-js@v2.1555.0...v2.1556.0)

---
updated-dependencies:
- dependency-name: aws-sdk
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]