Upgrade p256 to v0.12 (#90)

* Upgrade `p256` to v0.12

* Upgrade MSRV to 1.60

Cargo.toml

@@ -8,7 +8,7 @@ license = "MIT"
 name = "voprf"
 readme = "README.md"
 repository = "https://github.com/novifinancial/voprf/"
-rust-version = "1.57"
+rust-version = "1.60"
 version = "0.5.0-pre.1"
 
 [features]
@@ -45,7 +45,7 @@ zeroize = { version = "1.5", default-features = false }
 generic-array = { version = "0.14", features = ["more_lengths"] }
 hex = "0.4"
 json = "0.12"
-p256 = { version = "0.11", default-features = false, features = [
+p256 = { version = "0.12", default-features = false, features = [
   "hash2curve",
   "voprf",
 ] }