Hello!

Suppose I have the code from the doc, https://kristofferc.github.io/PGFPlotsX.jl/stable/examples/axislike/:

```
x = range(0; stop =2*pi, length = 100)
@pgf GroupPlot(
{
group_style =
{
group_size="2 by 1",
xticklabels_at="edge bottom",
yticklabels_at="edge left"
},
no_markers
},
{},
PlotInc(Table(x, sin.(x))),
PlotInc(Table(x, sin.(x .+ 0.5))),
{},
PlotInc(Table(x, cos.(x))),
PlotInc(Table(x, cos.(x .+ 0.5))))
```

Which produces:

How do I add a group title on top of it, similar to how I could use “plot_title”?

Kind regards