Preserve behavior regarding slashes on Windows

windows.ps1

@@ -7,8 +7,10 @@ $arm_exe_path = scoop which arm-none-eabi-gcc
 $arm_path = [System.IO.Path]::GetDirectoryName($arm_exe_path)
 $arm_path_resolved = Resolve-Path($arm_path) | select -ExpandProperty Path
 echo "$arm_path_resolved" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
-echo "Setting INSTALL_DIR to: $arm_path_resolved"
-echo "INSTALL_DIR=$arm_path_resolved" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
+$pattern = '[\\/]'
+$install_dir = $arm_path_resolved -replace $pattern, '/'
+echo "Setting INSTALL_DIR to: $install_dir"
+echo "INSTALL_DIR=$install_dir" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
 
 $version = arm-none-eabi-gcc --version | select -first 1
 echo "Setting VERSION to: $version"