Create releases as prereleases

Author: gsingh93

.github/workflows/build.yml

@@ -128,6 +128,7 @@ jobs:
     - name: Publish release
       uses: softprops/action-gh-release@v1
       with:
+        prerelease: true
         tag_name: ${{ steps.vars.outputs.DATE }}-${{ needs.build.outputs.SHORT_HASH }}
         files: |
           kernel-image/*