cubicweb-skillmat #5295679 improve colors [validation pending]

l4 (i am autonomous) should be light green and l5 (i can teach it) green, because they are similar.

currently l4 looks like l3, which is (i can use it)

prioritynormal
typeenhancement
done in0.9.0
load0.100
load left0.000
closed by#34d2d3bb87a5 css: improve colors (closes #5295679)
patchcss: improve colors (closes #5295679) [applied]