[Bug 43100] Release key overwrite

https://bugs.winehq.org/show_bug.cgi?id=43100

--- Comment #1 from Sebastian Lackner  ---
Thanks for the bug report. I've already added "-nc" to wget in the Ubuntu and
Debian installation instructions, however the best solution would be to avoid
any temporary files. Would it maybe be better to write it like:

wget -O- https://dl.winehq.org/wine-builds/Release.key | sudo apt-key add -

Or maybe, rely on "apt-key adv" to fetch the keys from a keyserver? Of course
we should make sure that the method works for all currently supported distro
versions. Suggestions are welcome.