Replace deprecated codecs.open by open

[FriedrichFroebel]

Running tests for one of my packages relying on mf2py with warnings enabled prints:

../../../../../opt/hostedtoolcache/Python/3.14.0/x64/lib/python3.14/site-packages/mf2py/backcompat.py:50: 11 warnings
  /opt/hostedtoolcache/Python/3.14.0/x64/lib/python3.14/site-packages/mf2py/backcompat.py:50: DeprecationWarning: codecs.open() is deprecated. Use open() instead.
    with codecs.open(file_path, "r", "utf-8") as f:

[ysamlan]

FYI, Python 3 open() takes encoding as a keyword argument, not positional. The third positional
parameter is buffering (expects an int), so this:

open(file_path, "r", "utf-8")

raises TypeError: 'str' object cannot be interpreted as an integer at import time on Python 3.14. Should be:

open(file_path, encoding="utf-8") ('r' is the default for mode, so that's optional).

> help(open)
Help on built-in function open in module _io:
open(
    file,
    mode='r',
    buffering=-1,
    encoding=None,
    errors=None,
    newline=None,
    closefd=True,
    opener=None
)

[FriedrichFroebel]

Thanks, I did not test the change back then. I have made all the optional parameters keywords.