bump min python to 3.10

pyproject.toml

pytools/__init__.py

pytools/codegen.py

pytools/convergence.py

pytools/datatable.py

pytools/graph.py

pytools/mpi.py

pytools/persistent_dict.py

pytools/spatial_btree.py

pytools/stopwatch.py

pytools/tag.py

pytools/test/test_data_table.py

pytools/test/test_graph_tools.py

pytools/test/test_persistent_dict.py

pytools/test/test_pytools.py