Update devcontainer.json

Author: jf205

.devcontainer/devcontainer.json

@@ -3,5 +3,10 @@
     "github.vscode-codeql",
     "vsls-contrib.codetour"
   ],
+  "customizations": {
+    "codespaces": {
+      "openFiles": ["tutorial.code-workspace"]
+    }
+  },
   "postCreateCommand": "bash .devcontainer/postCreateCommand.sh"
-}
+}