Update README.md

README.md

-# Libmorton v0.2.4
+# Libmorton v0.2.5
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  * Libmorton is a **C++ header-only library** with methods to efficiently encode/decode 64, 32 and 16-bit Morton codes and coordinates, in 2D and 3D. *Morton order* is also known as *Z-order* or *[the Z-order curve](https://en.wikipedia.org/wiki/Z-order_curve)*.