vscode add uavcan.dsdl to recommended extensions

- this extension adds support for Data Structure Description Language (DSDL)

.vscode/extensions.json

@@ -11,7 +11,8 @@
         "ms-vscode.cpptools",
         "peterjausovec.vscode-docker",
         "twxs.cmake",
+        "uavcan.dsdl",
         "vector-of-bool.cmake-tools",
         "wholroyd.jinja"
     ]
-}
+}