upgrade sbt plugins on 1.4.x branch (#904)

* Update plugins.sbt

* revert sbt-header change

* Update plugins.sbt

Author: pjfanning

project/plugins.sbt

@@ -17,19 +17,17 @@ addSbtPlugin("com.github.sbt" % "sbt-unidoc" % "0.6.0")
 addSbtPlugin("com.thoughtworks.sbt-api-mappings" % "sbt-api-mappings" % "3.0.2")
 addSbtPlugin("pl.project13.scala" % "sbt-jmh" % "0.4.7")
 addSbtPlugin("net.virtual-void" % "sbt-dependency-graph" % "0.10.0-RC1") // for advanced PR validation features
-addSbtPlugin("com.github.sbt" % "sbt-boilerplate" % "0.7.0")
+addSbtPlugin("com.github.sbt" % "sbt-boilerplate" % "0.8.0")
 addSbtPlugin("com.lightbend.sbt" % "sbt-bill-of-materials" % "1.0.2")
 addSbtPlugin("com.github.sbt" % "sbt-license-report" % "1.7.0")
 
 addSbtPlugin("org.apache.pekko" % "pekko-sbt-paradox" % "1.0.1")
 
 addSbtPlugin("de.heikoseeberger" % "sbt-header" % "5.10.0")
 addSbtPlugin("net.bzzt" % "sbt-reproducible-builds" % "0.32")
-addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.14.3")
-addSbtPlugin("com.github.sbt" % "sbt-dynver" % "5.1.1")
+addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.14.5")
 addSbtPlugin("com.github.pjfanning" % "sbt-source-dist" % "0.1.13")
-addSbtPlugin("com.github.pjfanning" % "sbt-pekko-build" % "0.4.5")
-addSbtPlugin("net.virtual-void" % "sbt-hackers-digest" % "0.1.2")
+addSbtPlugin("com.github.pjfanning" % "sbt-pekko-build" % "0.4.7")
 addSbtPlugin("com.lightbend.sbt" % "sbt-java-formatter" % "0.7.0")
 
 // used in ValidatePullRequest to check github PR comments whether to build all subprojects