Ticks don't always go to extrema, even when they should

[asinghvi17]

Consider the following:

fig = Figure();
ax = GeoAxis(fig[1, 1])
xlims!(0, 3)
ylims!(0, 3)
plot!(ax, Point2(1.5))

The axis limits are fine, but there is no tick at 3 degrees north which is a bit odd, considering that both 1 and 2 have ticks.
cc @alex-s-gardner

[asinghvi17]

This is specifically a tick finding issue, unrelated to the others.