build(deps): bump aws-lambda-powertools in /src/bulk_importer

Bumps [aws-lambda-powertools](https://github.com/aws-powertools/powertools-lambda-python) from 3.20.0 to 3.21.0.
- [Release notes](https://github.com/aws-powertools/powertools-lambda-python/releases)
- [Changelog](https://github.com/aws-powertools/powertools-lambda-python/blob/develop/CHANGELOG.md)
- [Commits](aws-powertools/powertools-lambda-python@v3.20.0...v3.21.0)

---
updated-dependencies:
- dependency-name: aws-lambda-powertools
  dependency-version: 3.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

src/bulk_importer/requirements.txt

@@ -1,2 +1,2 @@
 boto3==1.40.21
-aws_lambda_powertools==3.20.0
+aws_lambda_powertools==3.21.0