GitHub Actions windows-2019 runner is being retired (#617)

.github/workflows/bvt.yml

@@ -38,14 +38,14 @@ permissions:
 
 jobs:
   build:
-    runs-on: ${{ matrix.os }}
+    runs-on: windows-2022
     timeout-minutes: 60
 
     strategy:
       fail-fast: false
 
       matrix:
-        os: [windows-2019, windows-2022]
+        toolver: ['14.29', '14']
         build_type: [x64-Release]
         arch: [amd64]
 
@@ -65,6 +65,7 @@ jobs:
     - uses: ilammy/msvc-dev-cmd@0b201ec74fa43914dc39ae48a89fd1d8cb592756 # v1.13.0
       with:
         arch: ${{ matrix.arch }}
+        toolset: ${{ matrix.toolver }}
 
     - name: 'Set triplet'
       shell: pwsh