Mp3 is defined twice causing an error

If you have an issue with a specific extension or type

Locate the definition for your extension/type in the db.json file in the mime-db project. Does it look right?

[ ] No. File a mime-db issue. [x] Yes: Go ahead and submit your issue/PR here and I’ll look into it.

mp3 is defined in both audio/mp3 and audio/mpeg causing the following error:

Error: Attempt to change mapping for "mp3" extension from "audio/mp3" to "audio/mpeg". Pass force=true to allow this, otherwise remove "mp3" from the list of extensions for "audio/mpeg".

[broofa]

published in v2.3

[caub]

I found why, we need to copy types/standard.json, either JSON.parse(JSON.stringify(require('./types/standard'))) or something better in both mime and lite

or yea better, avoiding to mutate, like in your fix