This update for suse-build-key fixes the following issues:

- The SUSE Notary Container key is different from the build signing
key, include this key instead as suse-container-key. (PM-1845 bsc#1170347)

- The SUSE build key for SUSE Linux Enterprise 12 and 15 is extended by 4 more years. (bsc#1176759)

This update was imported from the SUSE:SLE-15:Update update project.