Update msbuild.yml

.github/workflows/msbuild.yml

@@ -47,7 +47,8 @@ jobs:
       run: msbuild /m /p:Configuration=${{env.BUILD_CONFIGURATION}} ${{env.SOLUTION_FILE_PATH}}
     
     - name: Set Date Environment Variable
-        run: set BUILDATE=%DATE:~10,4%%DATE:~4,2%%DATE:~7,2%
+        env:
+          BUILDATE: BUILDATE=%DATE:~10,4%-%DATE:~4,2%-%DATE:~7,2%
     
     - name: Create Release
         id: auto-build