Switch icon to white when browser is in dark mode on Chrome

[webysther]

based on #156 but for chrome:

ref.: https://stackoverflow.com/a/58882519 https://github.com/w3c/webextensions/issues/229#issuecomment-1544194742 https://github.com/w3c/webextensions/issues/229#issuecomment-1595911662

[janive]

I would also like to have the option to switch to an brighter icon. I use vivaldi with a dark theme.