Do not keep gh-pages history

Keeping the history of gh-pages adds a lot of bloat when trying to clone the repository. The force_orphan option added pushes just one commit with no prior history to the gh-pages branch on every change, which should significantly reduce the size of the repository.

Author: jackpot51

.github/workflows/deploy.yml

@@ -45,3 +45,4 @@ jobs:
           cname: support.system76.com
           github_token: ${{ secrets.RELEASE_TOKEN }}
           publish_dir: ./dist
+          force_orphan: true