Update sbt-github-actions to 0.28.0

Author: scala-steward

project/plugins.sbt

@@ -5,5 +5,5 @@
 addSbtPlugin("org.scalameta"  % "sbt-scalafmt"       % "2.5.5")
 addSbtPlugin("com.eed3si9n"   % "sbt-buildinfo"      % "0.13.1")
 addSbtPlugin("com.github.sbt" % "sbt-ci-release"     % "1.11.2")
-addSbtPlugin("com.github.sbt" % "sbt-github-actions" % "0.27.0")
+addSbtPlugin("com.github.sbt" % "sbt-github-actions" % "0.28.0")
 addSbtPlugin("ch.epfl.scala"  % "sbt-scalafix"       % "0.14.3")