ci(deps): bump actions/setup-dotnet from 5 to 6 (#759)

Bumps [actions/setup-dotnet](https://github.com/actions/setup-dotnet) from 5 to 6.
- [Release notes](https://github.com/actions/setup-dotnet/releases)
- [Commits](https://github.com/actions/setup-dotnet/compare/v5...v6)

---
updated-dependencies:
- dependency-name: actions/setup-dotnet
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/defender-for-devops.yml

@@ -37,7 +37,7 @@ jobs:
 
     steps:
     - uses: actions/checkout@v7
-    - uses: actions/setup-dotnet@v5
+    - uses: actions/setup-dotnet@v6
       with:
         dotnet-version: |
           5.0.x