Improve the caching mechanism

[Xiaokang2022]

When writing documentation, we may use the serve command to modify and preview the results in real time.

But this creates an annoying problem where the serve command rebuilds the document every time the document is modified, but the cached file is not saved every time, which results in duplicate fetching data from GitHub / GitLab, which is not good for live previews.

Perhaps, we need to change the time when the cache is saved. My understanding is that as long as there is fetching data in this build, then this build should save the cache file, but this is not the case.