Bump actions/attest-build-provenance from 2.0.0 to 2.1.0

Bumps [actions/attest-build-provenance](https://github.com/actions/attest-build-provenance) from 2.0.0 to 2.1.0.
- [Release notes](https://github.com/actions/attest-build-provenance/releases)
- [Changelog](https://github.com/actions/attest-build-provenance/blob/main/RELEASE.md)
- [Commits](actions/attest-build-provenance@619dbb2...7668571)

---
updated-dependencies:
- dependency-name: actions/attest-build-provenance
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

.github/workflows/release.yml

@@ -105,7 +105,7 @@ jobs:
         run: dotnet pack ${{ env.Project }} -c Release -o ${{ github.workspace }}/artifacts
       - name: Generate nupkg attestation
         if: steps.pack.outputs.canPack == 'true'
-        uses: actions/attest-build-provenance@619dbb2e03e0189af0c55118e7d3c5e129e99726 # v2.0.0
+        uses: actions/attest-build-provenance@7668571508540a607bdfd90a87a560489fe372eb # v2.1.0
         with:
           subject-path: ${{ github.workspace }}/artifacts
       - name: Upload nupkg