SUSE 12/15 Linux package repository broken: "File 'repomd.xml' from repository 'packages-microsoft-com-prod' is signed with an unknown key"

[dagood]

Trying to use the SUSE 12 feed (also reported for SUSE 15) to install any .NET Core package results in:

Refreshing service 'container-suseconnect-zypp'.
Retrieving repository 'packages-microsoft-com-prod' metadata --------------------------------------------------------[\]
Warning: File 'repomd.xml' from repository 'packages-microsoft-com-prod' is signed with an unknown key 'EB3E94ADBE1229CF'.

    Note: Signing data enables the recipient to verify that no modifications occurred after the data
    were signed. Accepting data with no, wrong or unknown signature can lead to a corrupted system
    and in extreme cases even to a system compromise.

    Note: File 'repomd.xml' is the repositories master index file. It ensures the integrity of the
    whole repo.

    Warning: We can't verify that no one meddled with this file, so it might not be trustworthy
    anymore! You should not continue unless you know it's safe.

File 'repomd.xml' from repository 'packages-microsoft-com-prod' is signed with an unknown key 'EB3E94ADBE1229CF'. Continue? [yes/no] (no):

I'm opening a ticket to get this fixed.

[dagood]

Opened https://icm.ad.msft.net/imp/v3/incidents/details/169864882/home (Microsoft-only link, here for tracking.)

[dagood]

The linux repo owners tracked this down to signing not having happened yet, and it's now fixed.