mime_content_type for CSV can be return 'text/html'

[nevigen]

This is:

- [x] a bug report

When CSV file contains fields with some html tags (for example "<a href=""..."">link</a>"), mime_content_type return 'text/html', not 'text/plain'. It need to add 'text/html' to array $supportedTypes in \PhpOffice\PhpSpreadsheet\Reader\Csv.php

        $type = mime_content_type($pFilename);
        $supportedTypes = [
            'text/html',
            'text/csv',
            'text/plain',
            'inode/x-empty',
        ];

        return in_array($type, $supportedTypes, true);

Which versions of PhpSpreadsheet and PHP are affected?

php 7 and last PhpSpreadsheet

[PowerKiKi]

Seems to duplicate #564.

If your file has a csv extension it will be read, otherwise we try our best to guess, but it's only that a guess. If you know it's a CSV, then create the reader yourself, instead of relying on IOFactory guesswork.

[dmitrystas]

File has CSV extension, but mime_content_type return 'text/html'