`rdump --list-adapters` breaks on Python >= 3.10

[yunzheng]

root@be377bfea76f:/# python --version
Python 3.11.0

root@be377bfea76f:/# rdump --list-adapters
Traceback (most recent call last):
  File "/usr/local/bin/rdump", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/usr/local/lib/python3.11/site-packages/flow/record/utils.py", line 57, in wrapper
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/flow/record/tools/rdump.py", line 163, in main
    list_adapters()
  File "/usr/local/lib/python3.11/site-packages/flow/record/tools/rdump.py", line 51, in list_adapters
    Path(name).stem for name in loader.contents() if name.endswith(("py", "pyc")) and not name.startswith("__")
                                ^^^^^^^^^^^^^^^
AttributeError: 'SourceFileLoader' object has no attribute 'contents'