New jekyll version incompatible

[YsHaNgM]

As jekyll 4.0 has dropped support of redcarpet, build fails with latest jekyll installed by gem.

[dpshelio]

Thanks for the heads up! We will evaluate whether to upgrade our version of jekyll, at the moment we are using 3.1.6 which is from 2016
https://github.com/UCL-RITS/research-computing-with-cpp/blob/d8206f29412892159b2633db966543f35d5f0678/.travis.yml#L36

[krishnakumarg1984]

As pointed out by the user YsHaNgM, Jekyll 4.0 onwards has dropped support for redcarpet. Could we perhaps move to Kramdown or Hugo?