Add __init__.py to make cirq.contrib.hacks a proper package (#5662)
Add __init__.py to make cirq.contrib.hacks a proper package (#5662)

Co-authored-by: Tanuj Khattar <ccaa23f66e6bbb53e78cd3e84729fd55f86a9f1f@google.com>
quantumlib/Cirq,quantumlib/Cirq,quantumlib/Cirq,quantumlib/Cirq,quantumlib/Cirq