Allow symfony/mime ^5.4 / Unlock contao 4.13 again

[zoglo]

Description

TL;DR:
Contao Haste in 5.2 is not installable on Contao 4.13

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#221 introduced symfony/mime as a dependency, however, the minimum requirements were set to ^6.0 || ^7.0.

Contao 4.13 needs symfony/mime in ^5.4.

I've installed the change on a 4.13 with symfony/mime ^5.4 installed and did run the tests:

There is also no BC changes in the MimeTypeGuesser:

• https://github.com/symfony/mime/blob/6.4/MimeTypesInterface.php
• https://github.com/symfony/mime/blob/6.4/FileinfoMimeTypeGuesser.php
• https://github.com/symfony/mime/blob/6.4/FileBinaryMimeTypeGuesser.php

Changelog:
https://github.com/symfony/mime/blob/6.4/CHANGELOG.md

[qzminski]

Thanks, released as 5.2.3.