Fix environment variable syntax for DOTNET_VERSION

Author: turbobobbytraykov

.github/workflows/build-and-publish.yml

@@ -26,7 +26,7 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: ${DOTNET_VERSION}
+          dotnet-version: ${{ env.DOTNET_VERSION }}
 
       - name: Build
         run: |