VersionAlert for Unity

Exposed public APIs for `SplineUtility.ReverseFlow`, `SplineUtility.JoinSplinesOnKnots`, and `SplineUtility.SplitSplineOnKnot`.

For Editor versions of 2023.2 or newer, added clipboard operations for Splines to the Scene view context menu.
Changed `Splines/Cycle Active Spline` shortcut to Shift-S to remove a conflict with Unity default shortcuts.
[SPLB-163] Improved performance of spline handles by caching spline data.
[SPLB-167] Changed the evaluation of up vectors to use a cache instead of re-evaluate the values on every single request.
In Editor versions of 2023.2 or newer, moved the following actions from the Element Inspector to the Scene view context menu: Link, Unlink, Split, Join, and Reverse Spline Flow.

[SPLB-176] Fixed a regression where the up vector would not evaluate correctly for some curves.
Fixed the setter for SplineAnimate.Normalized time to handle ping-pong direction correctly when set.
Fixed a bug where setting the time value to 0 after reaching the end of the spline animation was not resetting the object position.
[SPLB-169] Fixed a bug where `CurveUtility.GetNearestPoint` would return incorrect values for the interpolation.

com.unity.splines 2.4.0