chore(deps): update mcr.microsoft.com/devcontainers/javascript-node docker tag to v4 (#51)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| mcr.microsoft.com/devcontainers/javascript-node | image | major | `1-20` → `4-20` |

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### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update again.

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 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box

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Reviewed-on: #51
Co-authored-by: Renovate Bot <renovate@horstenkamp.eu>
Co-committed-by: Renovate Bot <renovate@horstenkamp.eu>

.devcontainer/devcontainer.json

@@ -1,6 +1,6 @@
 {
   "name": "JS Dev Container",
-  "image": "mcr.microsoft.com/devcontainers/javascript-node:1-20",
+  "image": "mcr.microsoft.com/devcontainers/javascript-node:4-20",
   "features": {
     "ghcr.io/devcontainers/features/git:1": {},
     "ghcr.io/devcontainers/features/git-lfs:1": {},