Merge pull request #338 from SethTisue/readme-scala3

mention 1.2 milestone and Scala 3 in readme

README.md

@@ -9,6 +9,10 @@
 
 This library was originally part of the Scala standard library, but is now community-maintained, under the guidance of the Scala team at Lightbend. If you are interested in helping please contact [@Philippus](https://github.com/philippus) or [@SethTisue](https://github.com/SethTisue).
 
+The latest stable release is 1.1.2.
+
+Experimental milestone 1.2.x milestones are available. Since 1.2.0-M1, Scala 3 is supported.
+
 ## Documentation
 
  * [Current API](https://javadoc.io/page/org.scala-lang.modules/scala-parser-combinators_2.12/latest/scala/util/parsing/combinator/index.html)