4.20.1

New features

[d82326c] Change the default theme to "auto" instead of "light" (@javiereguiluz)

Bug fixes

[cb9cc4e] Fix the handling of the icon using JavaScript in the slug field (@javiereguiluz)
[f7c0915] Fix menu item matcher when using pretty URLs and submenus (Valentin Karnauhov)
[ee475fb] Fix the design of the collapsed main menu (@javiereguiluz)
[03f593a] Update the Webpack Encore configuration (@javiereguiluz)
[b0a4d08] Update setup docs for developers not using Symfony Flex (@javiereguiluz)