[2.0.x]: Backport updates made by scala-steward (#326)

* Update sbt-assembly to 0.14.9 (#317)

* Update sbt-header to 5.2.0 (#320)

* Update assertj-core to 3.12.2 (#321)

* Update sbt-release to 1.0.11 (#318)

* Update sbt-mima-plugin to 0.3.0 (#319)

project/Dependencies.scala

@@ -6,7 +6,7 @@ import sbt._
 object Dependencies {
   val logback = Seq("ch.qos.logback" % "logback-core" % "1.2.3")
 
-  val assertj = Seq("org.assertj" % "assertj-core" % "3.12.1")
+  val assertj = Seq("org.assertj" % "assertj-core" % "3.12.2")
 
   val awaitility = Seq("org.awaitility" % "awaitility" % "3.1.6")
 

project/plugins.sbt

@@ -6,16 +6,16 @@ addSbtPlugin("org.xerial.sbt" % "sbt-sonatype" % "2.3")
 
 addSbtPlugin("com.jsuereth" % "sbt-pgp" % "1.1.2")
 
-addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.14.8")
+addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.14.9")
 
-addSbtPlugin("com.github.gseitz" % "sbt-release" % "1.0.9")
+addSbtPlugin("com.github.gseitz" % "sbt-release" % "1.0.11")
 
 addSbtPlugin("org.scalariform" % "sbt-scalariform" % "1.8.2")
 
-addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "0.1.18")
+addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "0.3.0")
 
 addSbtPlugin("com.gilt" % "sbt-dependency-graph-sugar" % "0.9.0")
 
-addSbtPlugin("de.heikoseeberger" % "sbt-header" % "5.0.0")
+addSbtPlugin("de.heikoseeberger" % "sbt-header" % "5.2.0")
 
 addSbtPlugin("pl.project13.scala" % "sbt-jmh" % "0.3.4")