Cannot use `.ts` file extension for custom-fields-parser

[Curs3W4ll]

Current behavior:

Hello,
While trying to use the --custom-fields-parser option, I tried to use a typescript file, but it doesn't work, throwing this error:

⠋ Generating types...
 Error

▲ error Unknown file extension ".ts" for /Users/myuser/dev/project/.storyblok/custom-fields-parser.ts

ℹ For more information about the error, run the command with the `--verbose` flag

But it's working fine with a .js file

Expected behavior:

Should work with typescript files

Steps to reproduce:

• Run the CLI with a typescript custom-fields-parser file, see the error showing