add size to comparison table

[ghost]

to me a good benefit of this project is the small size, at least in comparison to Hugo. currently the go.sum is 113 lines:

https://github.com/osteele/gojekyll/blob/main/go.sum

compared to Hugo, which is a ridiculous 859 lines:

https://github.com/gohugoio/hugo/blob/master/go.sum

[danog]

Hmm the size of the go.sum is indicative of the number of dependencies more than project size itself, which is calculated in another way, but will try to add something...