alignment: {:textRotation => 60}
That did it for me. I managed to find a similar issue from the axlsx github page: https://github.com/randym/axlsx/issues/110
I wasn't able to locate it in the docs.
The complete code can be implemented as follows:
my_style {
alignment: {:textRotation => 60, horizontal: :center, vertical: :center, wrap_text: true},
}
sheet.add_row(headers, style: styles[:my_style], height: height)