Open files with "b" flag

[hombit]

Bug report

File readers in file_io should open files with "rb" mode, e.g. here:

hats/src/hats/io/file_io/file_io.py

Line 121 in 8e1d456

with file_pointer.open("r", **kwargs) as csv_file:

Fixing this issue should also fix this one: astronomy-commons/hats-import#425

Before submitting
Please check the following:

• I have described the situation in which the bug arose, including what code was executed, information about my environment, and any applicable data others will need to reproduce the problem.
• I have included available evidence of the unexpected behavior (including error messages, screenshots, and/or plots) as well as a description of what I expected instead.
• If I have a solution in mind, I have provided an explanation and/or pseudocode and/or task list.