Add copyright notice to the top of each .py file.

[bje-]

Self-explanatory.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Files with missing lines	Coverage Δ
src/isp_workbook_parser/__init__.py	100.00% <ø> (ø)
src/isp_workbook_parser/config_model.py	100.00% <ø> (ø)
.../isp_workbook_parser/custom_string_replacements.py	100.00% <ø> (ø)
src/isp_workbook_parser/parser.py	89.14% <ø> (ø)
src/isp_workbook_parser/read_table.py	96.70% <ø> (ø)
src/isp_workbook_parser/sanitisers.py	100.00% <ø> (ø)

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[dylanjmcconnell]

Thanks @bje- seems fine / straightforward, but can you rebase this to latest version of main before I merge in?