Semver Minor Support for PEM/DER serialisation for asymmetric key types. Support for HKDF expand/extract. Brings API up to date with iOS 14. Semver Patch Updated to BoringSSL 54858b63c1d886f6c8d903d4a4f594f1485de189. (#47) Updated ECDSA signature code to use pure-Swift ASN.1 parsing/serialization. Fixed test running on Android. (#41) (patch credit to @buttaface) Documentation improvements. (#42, #44) (patch credit to @0xTim)