[#777] Trigger docs build on Git tag release
[#777] Trigger docs build on Git tag release

Related #777

## Changes:

- Trigger site build on tagged commit or master branch

htalat/Excalibur,htalat/Excalibur,excaliburjs/Excalibur,excaliburjs/Excalibur,htalat/Excalibur,excaliburjs/Excalibur