Some browsers download with garbled filename on attachment files

Summary

Some browsers download with garbled filename on attachment files.

Steps to reproduce

Example Project: https://gitlab.com/tailriver/test/issues/1

1. Upload テスト.txt by drag and drop.
2. Download テスト.txt from the link.
3. Check the filename.

What is the current bug behavior?

Download as 繝・せ繝・txt (e.g. Microsoft Edge)

What is the expected correct behavior?

Download as テスト.txt (e.g. Google Chrome)

Possible fixes

UTF-8 encoded filename may be interpreted as CP932 because my language setting is Japanese.

RFC 6266 based fix. filename*=utf-8'' in Content-Disposition header. (not verified)