don't rebuild from scratch each time

[lalitkapoor]

We should set the since option where possible to update the changelog. This will save on api calls and reduce time to generate the file.

Consider storing the since values directly in the markdown file as a comment or in another file. Read these values before building changelog.

Add a --rebuild flag to rebuild changelog from scratch (ignore since)

References:

Conditional requests

Most responses return an ETag header. Many responses also return a Last-Modified header. You can use the values of these headers to make subsequent requests to those resources using the If-None-Match and If-Modified-Since headers, respectively. If the resource has not changed, the server will return a 304 Not Modified. Also note: making a conditional request and receiving a 304 response does not count against your Rate Limit, so we encourage you to use it whenever possible.

http://developer.github.com/v3/#conditional-requests

[nunofgs]

Yes. Please add this 👍

[tunnckoCore]

Or just try to read and parse (meaning, get a latest version) local CHANGELOG file.

But yea, in long term maybe this would be better.