bump versions in doc

Author: bjornregnell

src/rootdoc.txt

@@ -19,8 +19,8 @@ This is the documentation of the `introprog` Scala library with beginner-friendl
 If you have [[https://www.scala-sbt.org/ `sbt`]] installed then you can put this text in a file called `build.sbt`
 
 {{{
-scalaVersion := "2.12.8"
-libraryDependencies += "se.lth.cs" %% "introprog" % "1.1.2"
+scalaVersion := "2.12.9"
+libraryDependencies += "se.lth.cs" %% "introprog" % "1.1.3"
 }}}
 
 When you run `sbt` in terminal the introprog lib is automatically downloaded and made available on your classpath.