remove upper bound on pyzmq

temporary pin applied to both jupyter-client 8 and pyzmq 25 _appears_ resolved with jupyter-client 7.49 (or jupyter-core 5.3.2?)

pinning pyzmq<25 prevents installation on Python 3.12, which requires pyzmq >=25.1

setup.py

@@ -109,7 +109,7 @@
         'tornado>=6.1',
         # pyzmq>=17 is not technically necessary,
         # but hopefully avoids incompatibilities with Tornado 5. April 2018
-        'pyzmq>=17,<25',
+        'pyzmq>=17',
         'argon2-cffi',
         'traitlets>=4.2.1',
         'jupyter_core>=4.6.1',