change release generation to be preprelease

Author: bckohan

.github/workflows/release.yml

@@ -132,6 +132,7 @@ jobs:
         '${{ github.ref_name }}'
         --repo '${{ github.repository }}'
         --generate-notes
+        --prerelease
     - name: Upload artifact signatures to GitHub Release
       env:
         GITHUB_TOKEN: ${{ github.token }}