History of hmac 1 change

In crates/hub/src/backups.rs, lines 442–447 on v0.6.1. Every change that wrote or deleted one of these lines, or deleted a line from between them. Exact, because each line keeps its identity across edits; edits elsewhere in the file are not here. Also: oxy log -L 442,447:crates/hub/src/backups.rs.