Re-vendor

vendor/github.com/pkg/errors/go113.go

@@ -1,71 +0,0 @@
-// +build go1.13
-
-package errors
-
-import (
-	stderrors "errors"
-)
-
-// Is reports whether any error in err's chain matches target.
-//
-// The chain consists of err itself followed by the sequence of errors obtained by
-// repeatedly calling Unwrap.
-//
-// An error is considered to match a target if it is equal to that target or if
-// it implements a method Is(error) bool such that Is(target) returns true.
-func Is(err, target error) bool { return stderrors.Is(err, target) }
-
-// As finds the first error in err's chain that matches target, and if so, sets
-// target to that error value and returns true.
-//
-// The chain consists of err itself followed by the sequence of errors obtained by
-// repeatedly calling Unwrap.
-//
-// An error matches target if the error's concrete value is assignable to the value
-// pointed to by target, or if the error has a method As(interface{}) bool such that
-// As(target) returns true. In the latter case, the As method is responsible for
-// setting target.
-//
-// As will panic if target is not a non-nil pointer to either a type that implements
-// error, or to any interface type. As returns false if err is nil.
-func As(err error, target interface{}) bool { return stderrors.As(err, target) }
-
-// Unwrap returns the result of calling the Unwrap method on err, if err's
-// type contains an Unwrap method returning error.
-// Otherwise, Unwrap returns nil.
-func Unwrap(err error) error {
-	return stderrors.Unwrap(err)
-}
-
-// Cause recursively unwraps an error chain and returns the underlying cause of
-// the error, if possible. There are two ways that an error value may provide a
-// cause. First, the error may implement the following interface:
-//
-//     type causer interface {
-//            Cause() error
-//     }
-//
-// Second, the error may return a non-nil value when passed as an argument to
-// the Unwrap function. This makes Cause forwards-compatible with Go 1.13 error
-// chains.
-//
-// If an error value satisfies both methods of unwrapping, Cause will use the
-// causer interface.
-//
-// If the error is nil, nil will be returned without further investigation.
-func Cause(err error) error {
-	type causer interface {
-		Cause() error
-	}
-
-	for err != nil {
-		if cause, ok := err.(causer); ok {
-			err = cause.Cause()
-		} else if unwrapped := Unwrap(err); unwrapped != nil {
-			err = unwrapped
-		} else {
-			break
-		}
-	}
-	return err
-}