build: remove TransformerDemo from installation (#373)
build: remove TransformerDemo from installation (#373)

We do not currently install any of the demos, remove the installation
for this particular demo.  We could introduce a new option to install
the demo programs, but given that they are demo programs, they are not
useful to install for persistence but more as a guide for getting
started.
tensorflow/swift-models,tensorflow/swift-models,tensorflow/swift-models,tensorflow/swift-models