MAINTAINERS: Update Juerg Haefliger's email address

Use my main @proton.me email address.

Signed-off-by: Juerg Haefliger <juergh@proton.me>
Link: https://lore.kernel.org/r/20220819055039.840221-1-juergh@proton.me


Signed-off-by: Guenter Roeck <linux@roeck-us.net>