Update README.md

Newer versions now accept double dashes and the single dashes are deprecated.

Otherwise it'll case a warning:

Warning: -norestore is deprecated.  Use --norestore instead.
Warning: -nologo is deprecated.  Use --nologo instead.
Warning: -norestore is deprecated.  Use --norestore instead.
Warning: -nofirststartwizard is deprecated.  Use --nofirststartwizard instead.
Warning: -accept=socket,port=2002;urp; is deprecated.  Use --accept=socket,port=2002;urp; instead.