No such file or directory when output-file contains directories that are not yet created

[benoitchantre]

When we run lightningcss from the CLI with the --output-file parameter, an error occurs when some directories of the output-file are missing.

To prevent the error, theses directories must exist before running lightningcss.

Would it be possible to create the required directories when they are missing?

[devongovett]

Seems reasonable.