[main] Bump Swashbuckle.AspNetCore in /eng/dependabot/independent (#7389)

Bumps [Swashbuckle.AspNetCore](https://github.com/domaindrivendev/Swashbuckle.AspNetCore) from 6.7.3 to 6.8.1.
- [Release notes](https://github.com/domaindrivendev/Swashbuckle.AspNetCore/releases)
- [Commits](domaindrivendev/Swashbuckle.AspNetCore@v6.7.3...v6.8.1)

---
updated-dependencies:
- dependency-name: Swashbuckle.AspNetCore
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

eng/dependabot/independent/Versions.props

@@ -15,7 +15,7 @@
     <!-- Third-party references -->
     <NewtonsoftJsonVersion>13.0.3</NewtonsoftJsonVersion>
     <NJsonSchemaVersion>11.0.0</NJsonSchemaVersion>
-    <SwashbuckleAspNetCoreVersion>6.7.3</SwashbuckleAspNetCoreVersion>
+    <SwashbuckleAspNetCoreVersion>6.8.1</SwashbuckleAspNetCoreVersion>
     <AwsSdkS3Version>3.7.305.7</AwsSdkS3Version>
     <AwsSdkSecurityTokenVersion>3.7.300.33</AwsSdkSecurityTokenVersion>