Skew is x-axis only, because it must be bidirectionally convertible to a 2x3 matrix, but you can subtract it to the rotation to get the effect on y-axis
(cherry picked from commit efb1f7d76b)
Happy new year to the wonderful Godot community!
We're starting a new decade with a well-established, non-profit, free
and open source game engine, and tons of further improvements in the
pipeline from hundreds of contributors.
Godot will keep getting better, and we're looking forward to all the
games that the community will keep developing and releasing with it.
Similarly to `Vector2` and `Rect2` transforms in 2D and Vector3, Plane,
and AABB in 3D. PoolVector2Array and PoolVector3Array were the only
missing Variant types in both Transform2D and Transform respectively.
This allows more consistency in the manner we include core headers,
where previously there would be a mix of absolute, relative and
include path-dependent includes.
