Update who-is-using-msys2.md: add Crown Engine

Author: dbartolini

web/docs/who-is-using-msys2.md

@@ -31,5 +31,6 @@
 * [darktable](https://www.darktable.org/) uses MSYS2 for its Windows releases and for CI ([Documentation](https://github.com/darktable-org/darktable/tree/master/packaging/windows))
 * [Mesh2HRTF](https://mesh2hrtf.sourceforge.io) uses MSYS2 for its Windows NumCalc [binaries](https://sourceforge.net/p/mesh2hrtf-tools/code/ci/master/tree/NumCalc_WindowsExe/) ([Documentation](https://sourceforge.net/p/mesh2hrtf/wiki/Installation_2/#compiling-numcalc-on-windows-using-msys2)).
 * [PVSnesLib](https://github.com/alekmaul/pvsneslib) uses MSYS2 to build ROMs on Windows
+* [Crown Engine](https://crownengine.org) uses MSYS2 for its Windows releases and for CI.
 
 *Feel free to add your project to this list!*