Returns the last year of commit activity grouped by week. The days array
is a group of commits per day, starting on Sunday.
GET /repos/:owner/:repo/stats/commit_activity
Status: 200 OK
[
{
"days": [
0,
3,
26,
20,
39,
1,
0
],
"total": 89,
"week": 1336280400
}
]