Fix pennylane-cirq name

Author: doctorperceptron

dependencies/constraints-dev.txt

@@ -4,7 +4,7 @@
 --extra-index-url https://download.pytorch.org/whl/cpu
 
 pennylane @ git+https://github.com/PennyLaneAI/pennylane.git#egg=pennylane
-cirq @ git+https://github.com/PennyLaneAI/pennylane-cirq.git#egg=pennylane-cirq
+pennylane-cirq @ git+https://github.com/PennyLaneAI/pennylane-cirq.git#egg=pennylane-cirq
 pennylane-qiskit @ git+https://github.com/PennyLaneAI/pennylane-qiskit.git#egg=pennylane-qiskit
 pennylane-qulacs @ git+https://github.com/PennyLaneAI/pennylane-qulacs.git#egg=pennylane-qulacs
 iqpot @ git+https://github.com/XanaduAI/iqpopt.git#egg=iqpopt