Bump elliptic-curve to v0.10; MSRV 1.51+ (#268)

Also updates the following:
- `p256` v0.9
- `p384` v0.8

src/lib.rs

@@ -14,7 +14,7 @@
 //!
 //! ## Minimum Supported Rust Version
 //!
-//! Rust 1.44+
+//! Rust **1.51** or newer.
 //!
 //! ## Supported YubiKeys
 //!
@@ -125,15 +125,9 @@
     html_logo_url = "https://raw.githubusercontent.com/iqlusioninc/yubikey.rs/main/img/logo.png",
     html_root_url = "https://docs.rs/yubikey/0.4.0-pre"
 )]
+#![allow(clippy::upper_case_acronyms)]
 #![forbid(unsafe_code)]
-#![warn(
-    missing_docs,
-    rust_2018_idioms,
-    trivial_casts,
-    trivial_numeric_casts,
-    unused_lifetimes,
-    unused_qualifications
-)]
+#![warn(missing_docs, rust_2018_idioms, trivial_casts, unused_qualifications)]
 
 mod apdu;
 pub mod cccid;

src/yubikey.rs

@@ -231,7 +231,7 @@ impl YubiKey {
     /// Begin a transaction.
     pub(crate) fn begin_transaction(&mut self) -> Result<Transaction<'_>, Error> {
         // TODO(tarcieri): reconnect support
-        Ok(Transaction::new(&mut self.card)?)
+        Transaction::new(&mut self.card)
     }
 
     /// Get the name of the associated PC/SC card reader