docs(examples): Note tmux version for environmental variables

Author: tony

docs/configuration/examples.md

@@ -262,9 +262,13 @@ please make a ticket on the [issue tracker][issue tracker].
 
 ## Environment variables
 
-tmuxp will set session, window and pane environment variables. Note that
-setting environment variables for windows and panes requires tmuxp 1.19 or
-newer.
+tmuxp will set session, window and pane environment variables.
+
+```{note}
+
+Setting environment variables for windows and panes requires tmuxp 1.19 or
+newer and tmux 3.0 or newer.
+```
 
 ````{tab} YAML