go: suggest adding GOROOT bin to PATH.

Closes #25508.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
gnupg: add mirror

ftp.gnupg.org is now inaccessible for more than 24 hours. add one of the official mirrors. (this one is in Switzerland)

Closes #25540.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>