Colorblind accessibility of colors

[jayqi]

We should use colorblind-accessible when possible.

For example, the test coverage color palette right now uses a red-green color scale.
https://github.com/UptakeOpenSource/pkgnet/blob/master/R/PackageFunctionReporter.R#L108

We could instead try to pick a colorblind safe color scheme from http://colorbrewer2.org

[bburns632]

@jayqi @jameslamb @patrick-boueri (and anyone!!) ,

What do you think of the color palette changing to this palette?

Thank you @jayqi for these simulations of this color palette under different color blindness conditions via https://www.color-blindness.com/coblis-color-blindness-simulator/:

[jameslamb]

I am comfortable with the palette you proposed, @bburns632 . This is a great change

[jameslamb]

For anyone coming to this issue from Google, I want to also note that you can list out all the colorblind palettes in RColorBrewer as follows:

RColorBrewer::display.brewer.all(colorblindFriendly=TRUE)

[jameslamb]

hey we can close this now that #141 was closed!