Raise MSRV to 1.55

Otherwise `cargo check` errors on the `-Wclippy::…` arguments from
`.cargo/config.toml`.
Usage as a dependency continues to work with 1.53 for now, but since
it's not changed this could soon change.

crates/ruma-state-res/.clippy.toml

@@ -1,4 +1,4 @@
-msrv = "1.53"
+msrv = "1.55"
 avoid-breaking-exported-api = false
 disallowed-types = []
 enforced-import-renames = [ { path = "serde_json::Value", rename = "JsonValue" } ]