Update tmux config to work with 2.9

tmux.conf

@@ -72,19 +72,14 @@ set-option -g assume-paste-time 0
 set -g display-time 2000
 
 # statusbar colors
-set -g status-bg black
-set -g status-fg yellow
-set -g status-attr default
-set -g pane-border-fg black
-set -g pane-active-border-fg brightgreen
-set -g message-bg black
-set -g message-fg brightred
+set -g status-style bg=black,fg=yellow,default
+set -g pane-border-style fg=black
+set -g pane-active-border-style fg=brightgreen
+set -g message-style bg=black,fg=brightred
 set -g display-panes-active-colour blue
 set -g display-panes-colour brightred
-setw -g window-status-fg white
-setw -g window-status-bg default
-setw -g window-status-current-fg brightred
-setw -g window-status-current-bg default
+setw -g window-status-style fg=white,bg=default
+setw -g window-status-current-style fg=brightred,bg=default
 setw -g clock-mode-colour green
 
 # Custom status bar