Support reposts_only filter for app.bsky.feed.getAuthorFeed

[xtianpu]

Is your feature request related to a problem? Please describe.

The need for reposts_only filter will be good to see what are user reposts only to know user interests.

Describe the solution you'd like

Support for reposts_only filter

Describe alternatives you've considered

Loop through all posts and check if app.bsky.feed.defs#reasonRepost does exist.