with `pg` option, dbfiles directory isn't created when absent

[jeremybmerrill]

❯ python -m congressionalrecord.cli 2020-01-01 2025-09-25 pg
Traceback (most recent call last):
  File "/Users/merrillj/.pyenv/versions/3.10.16/lib/python3.10/runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/Users/merrillj/.pyenv/versions/3.10.16/lib/python3.10/runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "/Users/merrillj/Projects/congressional-record/congressionalrecord/cli.py", line 79, in <module>
    main()
  File "/Users/merrillj/Projects/congressional-record/congressionalrecord/cli.py", line 67, in main
    cr(args.start, end=args.end, do_mode="yield")
  File "/Users/merrillj/Projects/congressional-record/congressionalrecord/pg_run/pg_cr_bulkwrite.py", line 155, in __init__
    pagestack = crPages(pagepath, self.page_fields)
  File "/Users/merrillj/Projects/congressional-record/congressionalrecord/pg_run/pg_cr_bulkwrite.py", line 39, in __init__
    self.outfile = open(outpath, "ab")
FileNotFoundError: [Errno 2] No such file or directory: 'dbfiles/pages.csv'

Ideally the dbfiles output dir would be created if it doesn't exist. (If I create it myself, everything seems to work just fine.)