History of sigv4 1 change

In crates/hub/src/backups.rs, lines 457–482 on 33d98147511b2f1705c62ca3f1b6b951a62567e8fbc8bd75acd7f02701b5f352. 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 457,482:crates/hub/src/backups.rs.