maintainers/scripts/sha-to-sri: drop unused imports

#!/usr/bin/env nix-shell

#! nix-shell -i "python3 -I" -p "python3.withPackages(p: with p; [ rich structlog ])"

from abc import ABC, abstractclassmethod, abstractmethod

from abc import ABC, abstractmethod

from contextlib import contextmanager

from pathlib import Path

from structlog.contextvars import bound_contextvars as log_context

_SKIP_RE = re.compile("(generated by)|(do not edit)", re.IGNORECASE)

if __name__ == "__main__":

    from sys import argv, stderr

    from sys import argv

    logger.info("Starting!")