Update vendors

vendor/github.com/peterh/liner/common.go

@@ -32,6 +32,7 @@ type commonState struct {
 	cursorRows        int
 	maxRows           int
 	shouldRestart     ShouldRestart
+	needRefresh       bool
 }
 
 // TabStyle is used to select how tab completions are displayed.
@@ -58,7 +59,17 @@ var ErrPromptAborted = errors.New("prompt aborted")
 // platform is normally supported, but stdout has been redirected
 var ErrNotTerminalOutput = errors.New("standard output is not a terminal")
 
-// Max elements to save on the killring
+// ErrInvalidPrompt is returned from Prompt or PasswordPrompt if the
+// prompt contains any unprintable runes (including substrings that could
+// be colour codes on some platforms).
+var ErrInvalidPrompt = errors.New("invalid prompt")
+
+// ErrInternal is returned when liner experiences an error that it cannot
+// handle. For example, if the number of colums becomes zero during an
+// active call to Prompt
+var ErrInternal = errors.New("liner: internal error")
+
+// KillRingMax is the max number of elements to save on the killring.
 const KillRingMax = 60
 
 // HistoryLimit is the maximum number of entries saved in the scrollback history.
@@ -133,6 +144,13 @@ func (s *State) AppendHistory(item string) {
 	}
 }
 
+// ClearHistory clears the scroollback history.
+func (s *State) ClearHistory() {
+	s.historyMutex.Lock()
+	defer s.historyMutex.Unlock()
+	s.history = nil
+}
+
 // Returns the history lines starting with prefix
 func (s *State) getHistoryByPrefix(prefix string) (ph []string) {
 	for _, h := range s.history {