ci: Add coverage for Qt 6.9

Qt has dropped support for vs2019, so drop it as well.

While we could workaround, let's instead give people some incentive
to update their toolchain so we can have less maintenance burden
of a FOSS project.

Author: iamsergio

.github/workflows/build.yml

@@ -20,7 +20,7 @@ jobs:
       matrix:
         os:
           - ubuntu-latest
-          - windows-2019
+          - windows-latest
           - macos-latest
         build_type:
           - Debug
@@ -36,7 +36,10 @@ jobs:
             qt_modules: qtscxml
             qt_arch: win64_msvc2019_64
             macos_architectures: "x86_64;arm64"
-
+          - qt_version: 6.9.0 # Bump to latest freely
+            qt_modules: qtscxml
+            qt_arch: win64_msvc2022_64
+            macos_architectures: "x86_64;arm64"
     steps:
       - name: Install Dependencies on Linux
         if: ${{ runner.os == 'Linux' }}