Update crates/core/Cargo.toml

Please disregard my suggestions. Looks like it's been fixed upstream.

Author: notmandatory

crates/core/Cargo.toml

@@ -13,7 +13,7 @@ readme = "README.md"
 [dependencies]
 bitcoin = { version = "0.32", default-features = false }
 serde = { version = "1", optional = true, features = ["derive", "rc"] }
-hashbrown = { version = "0.15", optional = true }
+hashbrown = { version = "=0.15.0", optional = true }
 
 [features]
 default = ["std"]