Really release v0.18.0-M2
Really release v0.18.0-M2

reactormonk/http4s,aeons/http4s,aeons/http4s,reactormonk/http4s,ChristopherDavenport/http4s,ChristopherDavenport/http4s,reactormonk/http4s,rossabaker/http4s,ChristopherDavenport/http4s,aeons/http4s,rossabaker/http4s,http4s/http4s