chore: upgrade to unsigned-varint 0.8 (#151)

Cargo.toml

@@ -12,7 +12,7 @@ rust-version = "1.60"
 
 [features]
 default = ["std"]
-std = ["alloc", "core2/alloc", "multihash/std"]
+std = ["alloc", "core2/alloc", "multihash/std", "unsigned-varint/std"]
 alloc = ["dep:multibase", "core2/alloc", "multihash/alloc"]
 arb = ["dep:arbitrary", "dep:quickcheck", "dep:rand", "multihash/arb"]
 scale-codec = ["dep:parity-scale-codec", "multihash/scale-codec"]
@@ -21,7 +21,7 @@ serde = ["alloc", "dep:serde", "dep:serde_bytes", "multihash/serde"]
 
 [dependencies]
 multihash = { version = "0.19.0", default-features = false }
-unsigned-varint = { version = "0.7.0", default-features = false }
+unsigned-varint = { version = "0.8.0", default-features = false }
 
 multibase = { version = "0.9.1", optional = true, default-features = false }
 parity-scale-codec = { version = "3.0.0", default-features = false, features = ["derive"], optional = true }