refactor: remove day node from events and repos per week

[sayanee]

It's always Monday anyway except for the first data in 2014!

Refer to:

• https://raw.githubusercontent.com/webuildsg/data/gh-pages/public/data/events-per-week.json
• https://raw.githubusercontent.com/webuildsg/data/gh-pages/public/data/repos-per-week.json

amend:

• events
• repos