std implies alloc (#242)

Author: johann-cm

serde_at/Cargo.toml

@@ -27,7 +27,7 @@ serde_bytes = { version = "0.11.14", default-features = false }
 [features]
 default = []
 custom-error-messages = []
-std = []
+std = ["alloc"]
 hex_str_arrays = []
 alloc = ["serde/alloc"]
 heapless = ["dep:heapless", "dep:heapless-bytes"]