Revert "Add github.com/json-iterator/go to vendor"

This reverts commit 43a9473a53.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

vendor/github.com/json-iterator/go/feature_json_number.go

@@ -1,31 +0,0 @@
-package jsoniter
-
-import (
-	"encoding/json"
-	"strconv"
-)
-
-type Number string
-
-// String returns the literal text of the number.
-func (n Number) String() string { return string(n) }
-
-// Float64 returns the number as a float64.
-func (n Number) Float64() (float64, error) {
-	return strconv.ParseFloat(string(n), 64)
-}
-
-// Int64 returns the number as an int64.
-func (n Number) Int64() (int64, error) {
-	return strconv.ParseInt(string(n), 10, 64)
-}
-
-func CastJsonNumber(val interface{}) (string, bool) {
-	switch typedVal := val.(type) {
-	case json.Number:
-		return string(typedVal), true
-	case Number:
-		return string(typedVal), true
-	}
-	return "", false
-}