Host the update site on GH Pages

[hrj]

• host stable site
• host unstable site

[hrj]

I just pushed the update site to gh-pages.

The stable update URL is https://vrapper.github.io/update-site/vrapper-stable/

Seems to work fine in my tests. Please confirm.

If all is green, I can upload the unstable site as well.

[hrj]

@keforbes Thanks for the new release this week.

I see that you pushed to the update-site folder. The update URL ( https://vrapper.github.io/update-site/vrapper-stable/ ) is working fine for me with Eclipse Photon.