added example (#7)

Co-authored-by: kjuulh <contact@kjuulh.io>
Reviewed-on: https://git.front.kjuulh.io/kjuulh/kraken/pulls/7

_examples/actions/write_a_readme/main.go

@@ -0,0 +1,9 @@
+package main
+
+import "github.com/bitfield/script"
+
+func main() {
+	script.
+		Echo("# Readme").
+		WriteFile("README.md")
+}