readme: note that large datasets may timeout db connection
readme: note that large datasets may timeout db connection

The readme notes already speaks to this by specifying that
publish-counts is intended for small datasets.  Reuse the existing note
to clarify the effect of publish-counts and counting large datasets.

Signed-off-by: Justin Charette <f8c1ccb28a9031959a9257227ce05d11006e6eca@gmail.com>

percolatestudio/publish-counts,boxofrox/publish-counts