refactor: rolling file appender to file appender

[tisonkun]

This closes #167

• SingleFile appender is removed. You can replace it with append::File.
• RollingFile is now File and provided by default.
• File appender now requires filename when constructing.
• File's filename_prefix is now renamed to mandatory filename.
• File's max_log_files now takes NonZeroUsize.
• File's rollover strategy methods are changed:
  • max_file_size -> rollover_size
  • rotation -> rollover_minutely, rollover_hourly, rollover_daily
  • By default, no rollover is performed.

[tisonkun]

cc @nine9ths FYI

cc @bearomorphism I took over this issue since I'd cut a release recently.

[bearomorphism]

I'm also a little busy lately so I haven't started working on this issue
No problem

[tisonkun]

cc @nine9ths @zuston Logforth 0.28.0 is now released.

Several interfaces has been changed but all should be documented in the CHANGELOG.md.

You may try it out and I'd expect one more breaking version to refine all the core APIs (e.g., LevelFilters).

[zuston]

cc @nine9ths @zuston Logforth 0.28.0 is now released.

Several interfaces has been changed but all should be documented in the CHANGELOG.md.

You may try it out and I'd expect one more breaking version to refine all the core APIs (e.g., LevelFilters).

got it. thanks for your mention