Escape text in custom module

[sespiros]

When having the following line in a custom module:

        "exec": "echo 'test1 & test2'",

running waybar results in:

(waybar:3775754): Gtk-WARNING **: 01:21:03.702: Failed to set text 'test1 & test2 ' from markup due to error parsing markup: Error on line 1: Entity did not end with a semicolon; most likely you used an ampersand character without intending to start an entity — escape ampersand as &