Update changelog generator script

[xPaw]

• Add support for optional deps (puts them in as normal dep)
• Updates for renovate bot (it currently still fails for babel monorepo)
• Fixed website repo name
• Split pull request query into chunks (100 prs per request) as github api was failing

[astorije]

This is awesome, thanks a lot @xPaw! Will look at the changes in more details.

[xPaw]

@astorije Merge yourself whenever.