Update sbt-coveralls to 1.3.15 (#1243)

Author: scala-steward

project/plugins.sbt

@@ -11,7 +11,7 @@ addSbtPlugin("com.github.sbt" % "sbt-pgp" % "2.3.1")
 addSbtPlugin("pl.project13.scala" % "sbt-jmh" % "0.4.7")
 addSbtPlugin("org.scoverage" % "sbt-scoverage" % "2.3.0")
 addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "1.1.4")
-addSbtPlugin("org.scoverage" % "sbt-coveralls" % "1.3.14")
+addSbtPlugin("org.scoverage" % "sbt-coveralls" % "1.3.15")
 addSbtPlugin("com.evolution" % "sbt-artifactory-plugin" % "0.0.2")
 addSbtPlugin("com.github.sbt" % "sbt-git" % "2.1.0")
 addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "2.3.1")