fix(docs): correct aukio-3d version in install snippet

fix(docs): correct aukio-3d version in install snippet

The install snippet told readers to depend on aukio-3d 1.4, which
was never released; the current version is 1.0.0. The Update web
site script now cds to its own directory first, so it can be invoked
from anywhere (e.g. a file manager) and still find the project root.