Bug: /contributors will return different result in China and USA

[liuxiran]

Bug performance:

when we visit https://www.apiseven.com/zh/contributor-graph?chart=contributorOverTime&repo=apache/apisix, we will get different result in China and USA.

In China, we will get 191, and in USA we will get 193

Analyse

After discussed in offline meeting, we found that, we used different CDN before our contributor-graph site, in Asian, we used Azure CDN, and others used Google CDN.

The problem is that the CDN cache in Azure is not updated.

TODO

We should provide a reasonable cache update mechanism, e.g. update cache regularly, or update cache when the data is updated.

At the same time, we also need to consider if we need to replace Asian to other CDN. If we decide to do so , please offer a more detailed comparison. Thanks.