Switch to downloading prebuilt release artifacts instead of a submodule

scripts/build-arch.bat

@@ -25,6 +25,12 @@ if /I "%BUILD_CONFIG%"=="debug" (
                 echo Signed release builds must not have unstaged changes!
                 exit /b 1
             )
+
+            echo Updating dependencies
+            powershell %cd%\setup-deps.ps1
+            if !ERRORLEVEL! NEQ 0 (
+                exit /b 1
+            )
         ) else (
             echo Invalid build configuration - expected 'debug' or 'release'
             echo Usage: scripts\build-arch.bat ^(release^|debug^)