Bump slsa-framework/slsa-github-generator from 1.5.0 to 1.6.0

Bumps [slsa-framework/slsa-github-generator](https://github.com/slsa-framework/slsa-github-generator) from 1.5.0 to 1.6.0.
- [Release notes](https://github.com/slsa-framework/slsa-github-generator/releases)
- [Changelog](https://github.com/slsa-framework/slsa-github-generator/blob/main/CHANGELOG.md)
- [Commits](https://github.com/slsa-framework/slsa-github-generator/compare/v1.5.0...v1.6.0)

---
updated-dependencies:
- dependency-name: slsa-framework/slsa-github-generator
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

.github/workflows/publish.yaml

@@ -33,7 +33,7 @@ jobs:
       id-token: write
       contents: write
     # Can't pin with hash due to how this workflow works.
-    uses: slsa-framework/slsa-github-generator/.github/workflows/generator_generic_slsa3.yml@v1.5.0
+    uses: slsa-framework/slsa-github-generator/.github/workflows/generator_generic_slsa3.yml@v1.6.0
     with:
       base64-subjects: ${{ needs.build.outputs.hash }}
   create-release: