Enable sending file contents in editMessageMedia

[versilov]

Like this: ExGram.editMessageMedia(%InputMedia{type: "photo", media: "attach://file"}, file: {:file_contents, <<>>, "img.gif"}, ...)

This is a quick fix. It would be nice to be able to do ExGram.editMessageMedia(%InputMedia{type: "photo", media: {:file_contents, <<>>, "img.gif"}}, ...) finally