Removed fuzztarget feature

It seems to be unused and when there's a need for it it's better to use
`--cfg fuzzing` as in `rust-secp256k1 ` and `bitcoin_hashes`.

Cargo.toml

@@ -14,7 +14,6 @@ readme = "README.md"
 [features]
 default = [ "std", "secp-recovery" ]
 base64 = [ "base64-compat" ]
-fuzztarget = []
 unstable = []
 rand = ["secp256k1/rand-std"]
 use-serde = ["serde", "bitcoin_hashes/serde", "secp256k1/serde"]

fuzz/Cargo.toml

@@ -14,7 +14,7 @@ honggfuzz_fuzz = ["honggfuzz"]
 [dependencies]
 honggfuzz = { version = "0.5", optional = true }
 afl = { version = "0.4", optional = true }
-bitcoin = { path = "..", features = ["fuzztarget"] }
+bitcoin = { path = ".." }
 
 # Prevent this from interfering with workspaces
 [workspace]