fix(devcontainer): moved settings to customizations/vscode (#21512)

The current configuration use the deprecated top-level `settings` and
`extensions` keys. Those are now under `customizations/vscode`.

.devcontainer/devcontainer.json

@@ -4,23 +4,23 @@
     "dockerfile": "Dockerfile"
   },
   "runArgs": ["--cap-add=SYS_PTRACE", "--security-opt", "seccomp=unconfined"],
-
-  "settings": {
-    "lldb.executable": "/usr/bin/lldb",
-    // VS Code don't watch files under ./target
-    "files.watcherExclude": {
-      "**/target/**": true
+  "customizations": {
+    "vscode": {
+      "settings": {
+        "lldb.executable": "/usr/bin/lldb",
+        // VS Code don't watch files under ./target
+        "files.watcherExclude": {
+          "**/target/**": true
+        },
+        "extensions": [
+          "rust-lang.rust-analyzer",
+          "tamasfe.even-better-toml",
+          "vadimcn.vscode-lldb",
+          "mutantdino.resourcemonitor"
+        ]
+      }
     }
   },
-
-  "extensions": [
-    "rust-lang.rust-analyzer",
-    "tamasfe.even-better-toml",
-    "vadimcn.vscode-lldb",
-    "mutantdino.resourcemonitor"
-  ],
-
   "postCreateCommand": "git submodule update --init",
-
   "remoteUser": "vscode"
 }