Prevent extra copies of files in gitlab "pages" deploys

This came up on !766 (merged), the files are being published to a public folder, and that folder gets copied on each language pass. The easiest way to see it is to download the archive.zip from a gitlab CI build and find all the copies of feed.xml, you'll see something like zh_Hans/public/en/feed.xml in addition to zh_Hans/feed.xml. This adds public to exclude to prevent it begin copied redundantly in to each language on gitlab pages deploys