dependabot-devcontainer: bump ubuntu in /.devcontainer

Bumps ubuntu from 22.04 to 24.04.

---
updated-dependencies:
- dependency-name: ubuntu
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.devcontainer/Dockerfile

@@ -1 +1 @@
-FROM ubuntu:22.04
+FROM ubuntu:24.04