Create plot layout with no separation between plots

Use Measures and bottom_margin (or top_margin):

using Measures, Plots

p1 = plot(rand(10),rand(10), xformatter=Returns(""))
p2 = plot(rand(10),rand(10),xformatter=Returns(""))
plot(p1,p2,layout=Plots.grid(2,1,heights=[0.2,0.8]), bottom_margin=[-7mm 0mm])