Update devcontainer.json with base image

Author: npv2k1

templates/ubuntu-dev/.devcontainer/devcontainer.json

@@ -3,11 +3,11 @@
 {
   "name": "Ubuntu",
   // Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
-  // "image": "mcr.microsoft.com/devcontainers/base:jammy",
-  "build": {
-    // Path is relative to the devcontainer.json file.
-    "dockerfile": "Dockerfile"
-  },
+  "image": "mcr.microsoft.com/devcontainers/base:jammy",
+  // "build": {
+  //   // Path is relative to the devcontainer.json file.
+  //   "dockerfile": "Dockerfile"
+  // },
   "features": {
     "ghcr.io/devcontainers/features/common-utils": {},