Try adding msbuild setup as a workflow step

Author: fwal

.github/workflows/ci.yml

@@ -43,6 +43,9 @@ jobs:
           node-version-file: ".nvmrc"
       - run: npm install
       - run: npm run build && npm run pack-source-map
+      - name: Add msbuild to PATH
+        if: ${{ matrix.os == 'windows-latest' || matrix.os == 'windows-11-arm' }}
+        uses: microsoft/setup-msbuild@v2
       - uses: ./
         with:
           swift-version: ${{ matrix.swift }}