Update subxt requirement from 0.33 to 0.34 (#27)

Cargo.toml

@@ -14,7 +14,7 @@ include = ["src/**/*", "LICENSE", "README.md"]
 [dependencies]
 codec = { package = "parity-scale-codec", version = "3"  }
 futures = "0.3"
-subxt = { version = "0.33", features = ["substrate-compat"] }
+subxt = { version = "0.34", features = ["substrate-compat"] }
 
 [dev-dependencies]
 clap = { version = "4", features = ["derive"] }