Update file-type dependency to >21.3.1 to fix security vulnerability

[adnweedon]

This package is currently locked to "file-type": "^16.5.4", which is affected by a security vulnerability GHSA-5v7r-6r5c-r473

Please could it be updated to ^21.3.1 to pull in the patched version!

[markrzen]

Related to #596