chore: update devcontainer.json

[hugo-sid]

What problem does this PR solve?

Upgrades Node JS version to 20.

Is this PR adding a new feature?

No

Is this PR related to any issue or discussion?

#260

PR Checklist

• I have verified that the code works as described/as intended.
• This change adds a social icon which has a permissive license to use it.
• This change does not include any external library/resources.
• This change does not include any unrelated scripts (e.g. bash and python scripts).
• I have enabled maintainer edits for this PR.

[netlify]

✅ Deploy Preview for hugo-blog-awesome ready!

Name	Link
🔨 Latest commit	646e9dd
🔍 Latest deploy log	https://app.netlify.com/sites/hugo-blog-awesome/deploys/675dd1f0479c5300088313e8
😎 Deploy Preview	https://deploy-preview-264--hugo-blog-awesome.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud