chore: update delegate requirement from 0.8.0 to 0.9.0 (#494)

Author: dependabot[bot]

Cargo.toml

@@ -27,7 +27,7 @@ serde_json = {version = "1.0.67", optional = true}
 bincode = {version = "1.3.1", optional = true}
 tskit-derive = {version = "0.2.0", path = "tskit-derive", optional = true}
 mbox = "0.6.0"
-delegate = "0.8.0"
+delegate = "0.9.0"
 
 [dev-dependencies]
 anyhow = {version = "1.0.66"}