csl: Removed coursier to fix the build

Summary: Problem

There seems to be a bug with sbt 1.0.x, sbt-pgp, and coursier.
See coursier/coursier#694

Solution

Stop using coursier to unblock publishing.

JIRA Issues: CSL-5520

Differential Revision: https://phabricator.twitter.biz/D112092

project/plugins.sbt

@@ -4,6 +4,7 @@ resolvers ++= Seq(
 )
 
 addSbtPlugin("com.typesafe.sbt" % "sbt-site" % "1.3.0")
-addSbtPlugin("io.get-coursier" % "sbt-coursier" % "1.0.0-RC12")
+// removed until https://github.com/sbt/sbt/issues/3496 is fixed
+// addSbtPlugin("io.get-coursier" % "sbt-coursier" % "1.0.0-RC12")
 addSbtPlugin("org.scoverage" % "sbt-scoverage" % "1.5.1")
 addSbtPlugin("com.eed3si9n" % "sbt-unidoc" % "0.4.1")