fix: support uploading files with non-ascii characters in their filenames

[syehoonkim]

With default multer, uploaded files' names with non-ascii show broken.
To fix, I changed encoding option from latin1 to utf8.
Please consider this.
Thank you.

[from-the-river-to-the-sea]

Based on expressjs/multer#1104, this PR seems correct.

Thank you for your contribution! 🙂

[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (ce84fd2) 70.33% compared to head (8621bf4) 70.33%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #655   +/-   ##
=======================================
  Coverage   70.33%   70.33%           
=======================================
  Files          33       33           
  Lines        1372     1372           
  Branches      288      288           
=======================================
  Hits          965      965           
  Misses        341      341           
  Partials       66       66           

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.

[from-the-river-to-the-sea]

Ah, can you make your changes on a branch not called master? Opening a pull request from one master branch to another tends to cause issues. Also, if you could revert the changes to package-lock.json and have only the changes to src/server/assets/index.ts, that would be good.

[syehoonkim]

Dear, I am a newbie on node.js and git, so I didn't know I should do that. Let me do that in short. Thank you.

[syehoonkim]

Am I doing right...??