[atlas] RIPE Atlas Anchor Certificate Change

Dear colleagues, We will be carrying out planned maintenance on RIPE Atlas anchors to replace the existing Lets Encrypt certificates with self-signed ones. There is no action needed by anchor hosts. The only visible change for users - should they want to visit an anchor URL using their browser - will be the standard notification asking them whether they trust the certificate before proceeding. This change is not expected to have a significant impact on functionality as the HTTPS service on RIPE Atlas anchors is not intended to be accessed by regular users in browsers but from measurements and scripts. Kind regards, Robert Kisteleki