Support webauthn (#17957)

Migrate from U2F to Webauthn

Co-authored-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

vendor/github.com/fxamacker/cbor/v2/doc.go

@@ -0,0 +1,109 @@
+// Copyright (c) Faye Amacker. All rights reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
+/*
+Package cbor is a fast & safe CBOR encoder & decoder (RFC 7049) with a
+standard API + toarray & keyasint struct tags, CBOR tags, float64->32->16,
+CTAP2 & Canonical CBOR, duplicate map key options, and is customizable via
+simple API.
+
+CBOR encoding options allow "preferred serialization" by encoding integers and floats
+to their smallest forms (like float16) when values fit.
+
+Struct tags like "keyasint", "toarray" and "omitempty" makes CBOR data smaller.
+
+For example, "toarray" makes struct fields encode to array elements.  And "keyasint"
+makes struct fields encode to elements of CBOR map with int keys.
+
+Basics
+
+Function signatures identical to encoding/json include:
+
+    Marshal, Unmarshal, NewEncoder, NewDecoder, encoder.Encode, decoder.Decode.
+
+Codec functions are available at package-level (using defaults) or by creating modes
+from options at runtime.
+
+"Mode" in this API means definite way of encoding or decoding. Specifically, EncMode or DecMode.
+
+EncMode and DecMode interfaces are created from EncOptions or DecOptions structs.  For example,
+
+    em := cbor.EncOptions{...}.EncMode()
+    em := cbor.CanonicalEncOptions().EncMode()
+    em := cbor.CTAP2EncOptions().EncMode()
+
+Modes use immutable options to avoid side-effects and simplify concurrency. Behavior of modes
+won't accidentally change at runtime after they're created.
+
+Modes are intended to be reused and are safe for concurrent use.
+
+EncMode and DecMode Interfaces
+
+    // EncMode interface uses immutable options and is safe for concurrent use.
+    type EncMode interface {
+	Marshal(v interface{}) ([]byte, error)
+	NewEncoder(w io.Writer) *Encoder
+	EncOptions() EncOptions  // returns copy of options
+    }
+
+    // DecMode interface uses immutable options and is safe for concurrent use.
+    type DecMode interface {
+	Unmarshal(data []byte, v interface{}) error
+	NewDecoder(r io.Reader) *Decoder
+	DecOptions() DecOptions  // returns copy of options
+    }
+
+Using Default Encoding Mode
+
+    b, err := cbor.Marshal(v)
+
+    encoder := cbor.NewEncoder(w)
+    err = encoder.Encode(v)
+
+Using Default Decoding Mode
+
+    err := cbor.Unmarshal(b, &v)
+
+    decoder := cbor.NewDecoder(r)
+    err = decoder.Decode(&v)
+
+Creating and Using Encoding Modes
+
+    // Create EncOptions using either struct literal or a function.
+    opts := cbor.CanonicalEncOptions()
+
+    // If needed, modify encoding options
+    opts.Time = cbor.TimeUnix
+
+    // Create reusable EncMode interface with immutable options, safe for concurrent use.
+    em, err := opts.EncMode()
+
+    // Use EncMode like encoding/json, with same function signatures.
+    b, err := em.Marshal(v)
+    // or
+    encoder := em.NewEncoder(w)
+    err := encoder.Encode(v)
+
+Default Options
+
+Default encoding options are listed at https://github.com/fxamacker/cbor#api
+
+Struct Tags
+
+Struct tags like `cbor:"name,omitempty"` and `json:"name,omitempty"` work as expected.
+If both struct tags are specified then `cbor` is used.
+
+Struct tags like "keyasint", "toarray", and "omitempty" make it easy to use
+very compact formats like COSE and CWT (CBOR Web Tokens) with structs.
+
+For example, "toarray" makes struct fields encode to array elements.  And "keyasint"
+makes struct fields encode to elements of CBOR map with int keys.
+
+https://raw.githubusercontent.com/fxamacker/images/master/cbor/v2.0.0/cbor_easy_api.png
+
+Tests and Fuzzing
+
+Over 375 tests are included in this package. Cover-guided fuzzing is handled by a separate package:
+fxamacker/cbor-fuzz.
+*/
+package cbor