Using `git ls-files | xargs dos2unix`. We should be consistently using
Unix line endings, not Windows ones.

Signed-off-by: Philip Withnall <philip.withnall@collabora.co.uk>
Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
Differential Revision: https://phabricator.apertis.org/D3938