Attempted fix by checking ERRORLEVEL env var

Author: abelbraaksma

.github/workflows/build.yaml

@@ -17,4 +17,8 @@ jobs:
         uses: actions/setup-dotnet@v3
       # build it, test it, pack it
       - name: Run dotnet build (release)
-        run: dotnet build ./src/FSharp.Control.TaskSeq.sln -c release 
+        run: ./build.cmd
+      - name: Check build result status
+        uses: technote-space/workflow-conclusion-action@v2
+        if: env.ERRORLEVEL != 0
+        run: exit 1