Missing support to constrain allowed content types.

[thet]

We can restrict the allowed content types for file inputs on upload time on the client side like so:

<input type="file" name="file" accept="audio/mp3, audio/flac" />

or:

<input type="file" name="image" accept="image/*" />

this package is currently missing support for that.

Related:

• Missing support to constrain allowed content types plone.namedfile#157
• Support for allowed content types. plone.namedfile#158
• Missing support to constrain allowed content types. plone.formwidget.namedfile#66
• Add support for accept attribute on file input. plone.formwidget.namedfile#67

[thet]

Fixed with: #200 and #199