History of sigv4 1 change

In crates/hub/src/backups.rs, lines 457–482 on faf5246c900e9ff6804832bff4ab4fc8188bad6a7220901e6209658ac70261c8. 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.