Revert "Revert "update jwt-go to v3.0.0-4-g01aeca5""

This reverts commit 7f456e49c9.

vendor/github.com/dgrijalva/jwt-go/errors.go

@@ -6,9 +6,9 @@ import (
 
 // Error constants
 var (
-	ErrInvalidKey       = errors.New("key is invalid or of invalid type")
-	ErrHashUnavailable  = errors.New("the requested hash function is unavailable")
-	ErrNoTokenInRequest = errors.New("no token present in request")
+	ErrInvalidKey      = errors.New("key is invalid")
+	ErrInvalidKeyType  = errors.New("key is of invalid type")
+	ErrHashUnavailable = errors.New("the requested hash function is unavailable")
 )
 
 // The errors that might occur when parsing and validating a token
@@ -16,22 +16,42 @@ const (
 	ValidationErrorMalformed        uint32 = 1 << iota // Token is malformed
 	ValidationErrorUnverifiable                        // Token could not be verified because of signing problems
 	ValidationErrorSignatureInvalid                    // Signature validation failed
-	ValidationErrorExpired                             // Exp validation failed
-	ValidationErrorNotValidYet                         // NBF validation failed
+
+	// Standard Claim validation errors
+	ValidationErrorAudience      // AUD validation failed
+	ValidationErrorExpired       // EXP validation failed
+	ValidationErrorIssuedAt      // IAT validation failed
+	ValidationErrorIssuer        // ISS validation failed
+	ValidationErrorNotValidYet   // NBF validation failed
+	ValidationErrorId            // JTI validation failed
+	ValidationErrorClaimsInvalid // Generic claims validation error
 )
 
+// Helper for constructing a ValidationError with a string error message
+func NewValidationError(errorText string, errorFlags uint32) *ValidationError {
+	return &ValidationError{
+		text:   errorText,
+		Errors: errorFlags,
+	}
+}
+
 // The error from Parse if token is not valid
 type ValidationError struct {
-	err    string
+	Inner  error  // stores the error returned by external dependencies, i.e.: KeyFunc
 	Errors uint32 // bitfield.  see ValidationError... constants
+	text   string // errors that do not have a valid error just have text
 }
 
 // Validation error is an error type
 func (e ValidationError) Error() string {
-	if e.err == "" {
+	if e.Inner != nil {
+		return e.Inner.Error()
+	} else if e.text != "" {
+		return e.text
+	} else {
 		return "token is invalid"
 	}
-	return e.err
+	return e.Inner.Error()
 }
 
 // No errors