investigate archiving old CI logs

[jdef]

When CI was migrated to github actions, it seems that the build logs do not have a long TTL - once they expire, they are lost, making it difficult to debug problems that may have crept in over time.

Ideally old CI logs would be archived somewhere easily mapped to builds of specific SHAs.

[humblec]

@jdef afaik, the logs are available for 90 days or so in public repos. if we need more than that, I think we have to store it some where.