Bump Swashbuckle.AspNetCore (#1538)

Bumps the dotnet group in /docs/extensibility/snippets/MailDevResourceWithCredentials with 1 update: [Swashbuckle.AspNetCore](https://github.com/domaindrivendev/Swashbuckle.AspNetCore).


Updates `Swashbuckle.AspNetCore` from 6.7.0 to 6.7.1
- [Release notes](https://github.com/domaindrivendev/Swashbuckle.AspNetCore/releases)
- [Commits](domaindrivendev/Swashbuckle.AspNetCore@v6.7.0...v6.7.1)

---
updated-dependencies:
- dependency-name: Swashbuckle.AspNetCore
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dotnet
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>