Nicegui

- close menu after click on menu item
- bugfixes

- introduction of `ui.colors` to configure primary, secondary colors
- allow dynamic creation of elements (for example add `ui.joystick` on button click)
- updated dependant packages to latest versions (fixes PIL security warning)
- allowing the customization of Quasar classes which are applied to the main page through new `ui.run` parameter `main_page_classes`

- introduction of `ui.open` to programatically switch between pages (see [example](https://nicegui.io/#open))
- headlines in the documentation now provide anchors for direct linking

- improve support for Python3.7
- new default port 8080

- print exceptions in coroutines registered for startup/shutdown
- fixed compatibility for Python <3.9

- showing exceptions from callables on startup/shutdown
- update parent view after async event handlers
- allow disabling repeating keyboard events to not clog the network