Fix devcontainer config (use vscode submenu)

.devcontainer/devcontainer.json

@@ -14,12 +14,11 @@
     "workspaceMount": "source=${localWorkspaceFolder},target=/workspaces/freqtrade,type=bind,consistency=cached",
     // Uncomment to connect as a non-root user if you've added one. See https://aka.ms/vscode-remote/containers/non-root.
     "remoteUser": "ftuser",
-
     "onCreateCommand": "pip install --user -e .",
     "postCreateCommand": "freqtrade create-userdir --userdir user_data/",
-
     "workspaceFolder": "/workspaces/freqtrade",
     "customizations": {
+        "vscode": {
             "settings": {
                 "terminal.integrated.shell.linux": "/bin/bash",
                 "editor.insertSpaces": true,
@@ -29,7 +28,6 @@
                 },
                 "python.pythonPath": "/usr/local/bin/python",
             },
-
             // Add the IDs of extensions you want installed when the container is created.
             "extensions": [
                 "ms-python.python",
@@ -40,3 +38,4 @@
             ],
         }
     }
+}