Update Rust crate similar-asserts to 1.6.0

Author: oxide-renovate[bot]

Cargo.lock

@@ -555,7 +555,7 @@ signal-hook = "0.3"
 signal-hook-tokio = { version = "0.3", features = [ "futures-v0_3" ] }
 sigpipe = "0.1.3"
 similar = { version = "2.6.0", features = ["bytes"] }
-similar-asserts = "1.5.0"
+similar-asserts = "1.6.0"
 # Don't change sled's version on accident; sled's on-disk format is not yet
 # stable and requires manual migrations. In the limit this won't matter because
 # the upgrade system will replace the DNS server zones entirely, but while we