[Doc]: Version switcher of the 3.6.0 page is not updated

### Documentation Link

https://matplotlib.org/stable/

### Problem

3.5 is still indicated as *stable*, 3.6 as *dev*

![grafik](https://user-images.githubusercontent.com/2836374/190866234-7bc70882-3231-4a38-ac27-1bc42cc5c757.png)


### Suggested improvement

_No response_