Revert "Squash deployed gh-pages, relying on this repo for history (#658)" (#663)

This reverts commit 5fc3cd7.

See discussion starting at
#658 (comment)

Author: jni

.github/workflows/build_and_deploy.yml

@@ -117,5 +117,4 @@ jobs:
           publish_dir: ./html
           publish_branch: gh-pages
           destination_dir: ${{ github.event.inputs.target_directory || 'dev' }}
-          force_orphan: true
           cname: napari.org