several improvements

- bump of sbt verstion
- switch to Junit jupiter
- added LRU cache

project/build.properties

@@ -1 +1 @@
-sbt.version=1.3.1
+sbt.version=1.4.1

project/build.scala

@@ -0,0 +1,5 @@
+object Versions {
+  val slf4j = "1.7.30"
+  val log4j = "2.13.2"
+  val lombok = "1.18.16"
+}

project/plugins.sbt

@@ -1,6 +1,8 @@
+resolvers += Resolver.jcenterRepo
 addSbtPlugin("com.jsuereth"      % "sbt-pgp"      % "1.1.0")
 addSbtPlugin("com.typesafe.sbt"  % "sbt-git"      % "0.9.3")
 addSbtPlugin("de.heikoseeberger" % "sbt-header"   % "4.1.0")
+addSbtPlugin("net.aichler" % "sbt-jupiter-interface" % "0.8.4-SNAPSHOT")
 addSbtPlugin("com.typesafe.sbt" % "sbt-native-packager" % "1.3.6")
 addSbtPlugin("com.thoughtworks.sbt" % "delombokjavadoc" % "1.0.0+66-8fbcf18c")