fix(deps): update rust crate libfuzzer-sys to 0.4 (#5)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

fuzz/Cargo.toml

@@ -9,7 +9,7 @@ edition = "2018"
 cargo-fuzz = true
 
 [dependencies]
-libfuzzer-sys = "0.3"
+libfuzzer-sys = "0.4"
 diffutils = { path = "../" }
 
 # Prevent this from interfering with workspaces