Update generic-ec version & bump own version

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "slip-10"
-version = "0.4.0-rc4"
+version = "0.4.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "SLIP10 implementation in Rust"
@@ -9,7 +9,7 @@ repository = "https://github.com/dfns/slip-10"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-generic-ec = { version = "0.4.0-rc4", default-features = false }
+generic-ec = { version = "0.4.0", default-features = false }
 
 hmac = { version = "0.12", default-features = false }
 sha2 = { version = "0.10", default-features = false }
@@ -35,7 +35,3 @@ required-features = ["all-curves"]
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs", "--html-in-header", "katex-header.html"]
-
-[patch.crates-io.generic-ec]
-git = "https://github.com/dfns/generic-ec"
-branch = "update-udigest"