update to use handlebars v5 (#1087)

Cargo.toml

@@ -47,7 +47,7 @@ pretty_env_logger = "0.5"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 tracing-log = "0.2"
 serde_derive = "1.0"
-handlebars = "4.0"
+handlebars = "5.0"
 tokio = { version = "1.0", features = ["macros", "rt-multi-thread"] }
 tokio-stream = { version = "0.1.1", features = ["net"] }
 listenfd = "1.0"