* Add 'make update-webassets' script
Copying over from `teleport/ops` to make it easier to discover.
Also changed the script to clone the repos into a temp directory and
clean it up later. Without this, a nested `teleport` checkout would
cause all kinds of problems.
* Update Makefile
Co-authored-by: Gus Luxton <gus@gravitational.com>
Co-authored-by: Gus Luxton <gus@gravitational.com>
