Zoom without CTRL/CMD

**Is your feature request related to a problem? Please describe.**
I am using `egui_plot` to draw a plot and currently have to press ctrl/cmd in order to zoom in and out with the scroll wheel.

**Describe the solution you'd like**
I want to zoom in and out with the scroll wheel directly without having to press ctrl/cmd.

**Describe alternatives you've considered**
Somehow hacking that in myself. But this got even harder because now scrolling is done by egui and seems to be strictly coupled with ctrl/cmd.