Tutorial 1 fails on Cirq 0.8: cirq.Rz

[drewrisinger]

As of cirq 0.7, cirq.Rz has been renamed to cirq.rz, which now fails on cirq 0.8. This causes the examples/tutorial_1_basis_change.ipynb notebook test to fail.

Failure log: https://travis-ci.org/github/drewrisinger/nur-packages/jobs/684259980#L4691-L4728