Generate html stats

[aaditkamat]

Closes #157

[pseusys]

Could you please provide us with motivation behind this PR?
The original purpose of this action is altering user README.md file, that uses markdown syntax, not HTML. Why should we mix these two?
Maybe we shoud add possibility to build output of this action with both markdown and html (separate files) later instead?

[aaditkamat]

Hi @pseusys, I created issue #157 to explain the rationale behind the PR. Please feel free to have a look at that. I learned how to add sections using GFM later, so the changes made in this PR are optional. You can close the PR if you feel the changes aren't needed.

[pseusys]

So in the end you were able to achieve what you wanted using markdown syntax, weren't you?