Update Ubuntu from 18.04 to latest (currently 20.04)

[Vadorequest]

because 18.04 isn't supported by GHA anymore

[github-actions]

❌  Deployment FAILED
Commit 4971de4 failed to deploy Storybook static site to
click to see logs

[github-actions]

✅  Deployment SUCCESS
Commit 4971de4 successfully deployed Next.js app 🚀 to https://nrn-v2-mst-aptd-at-lcz-sty-c1-ifrad88uv-unly-oss.vercel.app
Deployment aliases (2): nrn-v2-mst-aptd-at-lcz-sty-c1-preview.vercel.app, nrn-v2-mst-aptd-at-lcz-sty-c1-update-ubuntu.vercel.app

[github-actions]

❌  E2E tests FAILED for commit 4971de4 previously deployed at https://nrn-v2-mst-aptd-at-lcz-sty-c1-ifrad88uv-unly-oss.vercel.app
Download artifacts (screenshots + videos) from checks section

[github-actions]

✅  Deployment SUCCESS
Commit 75d4bcf successfully deployed Next.js app 🚀 to https://nrn-v2-mst-aptd-at-lcz-sty-c1-nudjis4ng-unly-oss.vercel.app
Deployment aliases (2): nrn-v2-mst-aptd-at-lcz-sty-c1-preview.vercel.app, nrn-v2-mst-aptd-at-lcz-sty-c1-update-ubuntu.vercel.app

[github-actions]

✅  E2E tests SUCCESS for commit 75d4bcf previously deployed at https://nrn-v2-mst-aptd-at-lcz-sty-c1-nudjis4ng-unly-oss.vercel.app