Use git binary assigment

[Patrick-Beuks]

At the moment this library uses the mimetype to determine if a file is a text file
https://github.com/gitonomy/gitlib/blob/main/src/Gitonomy/Git/Blob.php#L106

This make for example the mimetype application/json be a binary type.

Git has build-in binary assignment for file. If possible it would be nice to use this.

One way to do it is with the git ls-files command

git ls-files <filePath> --eol --with-tree=<branch|commit|tree>

A normal file would output:

git ls-files composer.json --eol --with-tree=HEAD
i/lf    w/lf    attr/                   composer.json

A binary file would output:

git ls-files a.out --eol --with-tree=main
i/-text w/-text attr/                   a.out

Notice the -text attrubutes

[lyrixx]

Would you mind to submit a PR?

[Patrick-Beuks]

Created a PR. As stated in the PR instead of using the ls-files route it uses the direct implementation git uses to determine if content is binary.