Update windows build instructions

README.md

@@ -80,14 +80,14 @@ Reference: https://docs.microsoft.com/en-us/windows/win32/fileio/maximum-file-pa
 
 Install **Visual Studio 2022**; you can install it from the **Microsoft Store**. It can also install **git** and **CMake** for you.
 
-Use the following command inside `git-bash`:
-```git-bash
+Use the following command inside `Powershell`:
+```ps1
 # Checkout the code very close to the root to avoid windows long path issues...
 cd c:\
 git clone --recurse-submodules https://github.com/free-audio/clap-plugins c-p
 cd c-p
 
-scripts/build-gui.sh
+Powershell.exe -noexit -executionpolicy bypass -File .\scripts\build-gui.ps1
 ```
 
 ## Linux, using vcpkg (static)

scripts/build-gui.ps1

@@ -0,0 +1,3 @@
+vcpkg/vcpkg --overlay-triplets=vcpkg-overlay/triplets install --triplet x64-win-cp --host-triplet x64-win-cp '--x-buildtrees-root=C:\B' --allow-unsupported --recurse --clean-after-build 'qtbase[core,png,brotli,zstd,doubleconversion,gui,concurrent,appstore-compliant,network,freetype,testlib,freetype]' qtdeclarative
+cmake --preset $cmake_preset $cmake_options -DCLAP_PLUGIN_GUI_MODEL=$gui_model
+cmake --build --preset $cmake_preset --config Release --target clap-plugins