Bump @microsoft/kiota-serialization-multipart

Bumps [@microsoft/kiota-serialization-multipart](https://github.com/microsoft/kiota-typescript) from 1.0.0-preview.5 to 1.0.0-preview.6.
- [Release notes](https://github.com/microsoft/kiota-typescript/releases)
- [Commits](https://github.com/microsoft/kiota-typescript/compare/@microsoft/[email protected]...@microsoft/[email protected])

---
updated-dependencies:
- dependency-name: "@microsoft/kiota-serialization-multipart"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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