History of sigv4 1 change

In crates/hub/src/backups.rs, lines 457–482 on c26267b3aba6b2028df7ba79af75cc09348b112980d46d1e78b209cd446d5497. 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.