Update sbt-github-actions to 0.28.0

Author: scala-steward

project/plugins.sbt

@@ -9,4 +9,4 @@ addSbtPlugin("com.github.sbt" % "sbt-ci-release" % "1.11.2")
 addSbtPlugin("com.github.sbt" % "sbt-unidoc" % "0.6.0")
 addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "1.1.4")
 addSbtPlugin("com.timushev.sbt" % "sbt-updates" % "0.6.4")
-addSbtPlugin("com.github.sbt" % "sbt-github-actions" % "0.27.0")
+addSbtPlugin("com.github.sbt" % "sbt-github-actions" % "0.28.0")