Only check (s)css files in css/

Signed-off-by: Joas Schilling <coding@schilljs.com>

run-stylelint.sh

@@ -8,4 +8,5 @@ if [ -z "$STYLELINT" ]; then
 fi
 
 echo Checking stylesheets with $STYLELINT ...
-find -name "*.css" -print0 | xargs -0 $STYLELINT
+find css/ -name "*.css" -print0 | xargs -0 $STYLELINT
+find css/ -name "*.scss" -print0 | xargs -0 $STYLELINT