Update Rust crate syn to v2

spooky_bsp_derive/Cargo.toml

@@ -9,4 +9,4 @@ proc-macro = true
 [dependencies]
 proc-macro2 = "1.0.47"
 quote = "1.0.21"
-syn = { version = "1.0.103", features = ["derive"] }
+syn = { version = "2.0.55", features = ["derive"] }