DateTime support for band

[ValentinKaisermayer]

using Dates
using GLMakie
t = range(DateTime(2020); step=Hour(1), length=1000)
y = cumsum(randn(1000))

fig = Figure()
ax = Axis(fig[1,1])
lines!(t, y) # <-- works
band!(t, zeros(1000), y) # <-- does not
fig