Announcement: please replace ants v1.2.0 with v1.2.1

[panjf2000]

Dear users of ants

This is a notice about an issue of ants in GO modules, the v1.2.0 has been re-tagged with a new commit, which causes the checksum mismatch with Go modules and you may encounter this problem sometime, see #49 for details.

To cut a long story short, the quick fix for this issue is to replace the version of v1.2.0 with v1.2.1 in your go.mod, then you'll be free from the tiresome checksum mismatch problem.

I'm sorry for the inconvenience caused to you.