Resolve breaking change in tmux 3.2

In order to make the status bar transparent, the status-bg variable
was set to the default background color. However, with tmux 3.2 this
no longer has the intended effect, as mentioned in the release post:

> status-fg and status-bg are now applied before status-style rather
> than instead of; this means that if either is set to default the
> status-style colour will be used. To fix, replace status-bg default
> with status-style bg=default.

This commit fixes the issue by applying the suggestion.

See: tmux/tmux#2645

.config/tmux/tmux.conf

@@ -5,7 +5,7 @@ bind C-Space last-window # Screen-like binding for last window
 set -g base-index 1 # One-based window numbering
 set -g renumber-windows on
 set -s escape-time 0 # No delay for escape key press
-set -g default-terminal "tmux-256color"
+set -g default-terminal tmux-256color
 
 # Pane switching using vi bindings
 bind h select-pane -L
@@ -27,7 +27,7 @@ bind c new-window -c "#{pane_current_path}"
 bind r source-file ~/.config/tmux/tmux.conf \; display "Reloaded!"
 
 # Status bar
-set -g status-bg default
+set -g status-style bg=default
 set -g status-left ''
 set -g status-right '#{?client_prefix,#[bg=colour3],}#[fg=colour250] %H:%M ' # Show time & indicate prefix-chording
 set -g status-justify centre