Post-release of v0.1.3 by @lindseydew: set snapshot version

Setting snapshot version after @lindseydew published https://github.com/guardian/kcl-pekko-stream/releases/tag/v0.1.3

Author: gu-scala-library-release[bot]

version.sbt

@@ -1 +1 @@
-ThisBuild / version := "0.1.3"
+ThisBuild / version := "0.1.4-SNAPSHOT"