Time-base One Time Password (OTP) based on RFC6238 with an HMAC-SHA1 algorithm and a 6 digits code in OCAML

It relies on the Cryptokit library for cryptography operations, as well as the Base32 library for base32 encoding. The library generate a QR Code with the qrc library. It is tested against all test vectors provided in RFC 6238 and the test suite provides as well a dynamic test which requires the use of an client authenticator (like Google Authenticator or Microsoft Authenticator) as a final test.