Bring fuzzer up to date

fuzz/.gitignore

@@ -1,3 +1,4 @@
 
 target
-libfuzzer
+corpus
+artifacts

fuzz/Cargo.toml

@@ -3,9 +3,15 @@
 name = "url-fuzz"
 version = "0.0.1"
 authors = ["Automatically generated"]
+publish = false
+
+[package.metadata]
+cargo-fuzz = true
 
 [dependencies.url]
 path = ".."
+[dependencies.libfuzzer-sys]
+git = "https://github.com/rust-fuzz/libfuzzer-sys.git"
 
 [[bin]]
 name = "parse"