build(deps): bump @aws-sdk/client-s3 in /apps/OpenSignServer

Bumps [@aws-sdk/client-s3](https://github.com/aws/aws-sdk-js-v3/tree/HEAD/clients/client-s3) from 3.812.0 to 3.821.0.
- [Release notes](https://github.com/aws/aws-sdk-js-v3/releases)
- [Changelog](https://github.com/aws/aws-sdk-js-v3/blob/main/clients/client-s3/CHANGELOG.md)
- [Commits](https://github.com/aws/aws-sdk-js-v3/commits/v3.821.0/clients/client-s3)

---
updated-dependencies:
- dependency-name: "@aws-sdk/client-s3"
  dependency-version: 3.821.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]