link to 0.18.x docs

Author: yurique

website/src/main/resources/doc/index.md

@@ -80,6 +80,7 @@ object counter extends ScalaJSModule {
 
 ### Previous versions
 
+* [frontroute `v0.18.x`](https://frontroute.dev/v/0.18.x/) (Laminar 16.x)
 * [frontroute `v0.17.x`](https://frontroute.dev/v/0.17.x/) (Laminar 15.x)
 * [frontroute `v0.16.x`](https://frontroute.dev/v/0.16.x/)
 * [frontroute `v0.15.x`](https://frontroute.dev/v/0.15.x/)