Loosen NumPy version requirement to allow version 2 (#763)

Author: mhucka

requirements.txt

@@ -1,6 +1,8 @@
 absl-py
 cirq-core~=1.0
-numpy~=1.16
+numpy>=1.26.0
+# The global option to pybind11 makes it include CMake files in a location where
+# CMake will find them. It makes a crucial difference in some environments.
 pybind11[global]
 typing_extensions
 setuptools