Requirements for change_dump_date.py

[leoberhelman]

Drafting some requirements for change_dump_date.pyto help out with refactoring / unit-testing / regression testing:

General Requirements

Primary functionality: Remove fields from a UM file, generating an output UM file with only a subset of its initial fields in it.
Python version: >=3.10
Audience: Researchers / ACCESS model users
Mode of use: Offline. To be run manually by the user.
Interface type: CLI

Interface requirements

Inputs: Input file (positional argument) [UM file, required]
Outputs: Output file (output path provided by the --output option)
Options:
-o, --output: output path (if not provided a default output path is produced)
-y --year an integer year (starting a 1, only positive)
-m --month an integer month (int: 1 -12)
-d --day an integer month (int: 1-31)
-validate add the the functionality to skip the river fields validation.