Update setup.py to require Python>=3.10

Author: dwskoog

setup.py

@@ -17,7 +17,7 @@
       license='BSD',
       keywords='streams',
       packages=packages + tests,
-      python_requires='>=3.9',
+      python_requires='>=3.10',
       long_description=(open('README.rst').read() if exists('README.rst')
                         else ''),
       install_requires=list(open('requirements.txt').read().strip().split('\n')),