Update build image to support latest Ubuntu version in order to fix netlify build pipeline

[srishti-nema]

Please follow the general troubleshooting steps first:

• While reviewing Author page removal #152 , saw build failures, reason behind this is older unsupported build image in the initial step of the pipeline
• Can be changed by changing the settings within site settings on Netlify, on navigating to the build UI it says Page not found - You might not have permissions to see this page.

Bug reports:

Build failure due to netflify checks failing at initial step of the pipeline because of unsupported Ubuntu build image version.
Deploy logs : https://app.netlify.com/sites/leomvit/deploys/664094518358c70008c9322b
Reference links : https://answers.netlify.com/t/please-read-end-of-support-for-xenial-build-image-everything-you-need-to-know/68239/1