File block does not appear to allow uploads of .zip files

[bobbingwide]

In the development site for oik-plugins ( s.b/oikcom ) when I create a new plugin / theme version I need to be able to upload the .zip file for the given version. The File block doesn't seem to accept my .zip files via the direct upload button, but does using Add Media.

This was mentioned in the core editor channel https://wordpress.slack.com/archives/C02QB2JS7/p1543858471147900
but I didn't follow it up.

I wanted to find if .zip files were supported so added a bit of code in oik-block's site opinion logic to call get_allowed_mime_types.

This issue is to document the problem as something that needs further investigation.

[bobbingwide]