always ask for command when creating new window in tmux

tmux.conf

@@ -3,7 +3,7 @@
 unbind C-b
 set -g prefix C-z
 bind-key C-z send-prefix
-bind-key C command-prompt "new-window '%%'"
+bind-key c command-prompt "new-window '%%'"
 
 setw -g mode-keys vi
 set -g base-index 1