requirements: Use exclusive upper bound for optuna (#2661)

Optuna uses patch versions to release bugfixes[0],
set the cap for the next minor version.

[0] https://github.com/optuna/optuna/releases

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

requirements.txt

@@ -11,7 +11,7 @@ matplotlib<3.7.2
 modeci_mdf<0.5, >=0.3.4; (platform_machine == 'AMD64' or platform_machine == 'x86_64') and platform_python_implementation == 'CPython' and implementation_name == 'cpython'
 networkx<3.2
 numpy<1.22.5, >=1.19.0
-optuna<=3.1.0
+optuna<3.2.0
 pandas<2.0.2
 pillow<9.6.0
 pint<0.21.0