chore(deps): update ncipollo/release-action # v1.21.0

Author: renovate[bot]

.github/workflows/ci-release.yml

@@ -74,7 +74,7 @@ jobs:
           done
 
       - name: "Publish release ${{ inputs.release_tags }}"
-        uses: ncipollo/release-action@b7eabc95ff50cbeeedec83973935c8f306dfcd0b # v1.20.0
+        uses: ncipollo/release-action@339a81892b84b4eeb0f6e744e4574d79d0d9b8dd # v1.21.0
         with:
           prerelease: false
           artifacts: release-artifacts/iperf3-*[!\.url]