[news] Add news about LTest that was missing in previous MR

_events/ltest-0.1.md

+---
+layout: default
+date: 08-04-2022
+short_title: LTest is out
+title: Release of LTest 0.1
+link: /fc-plugins/ltest.html
+---
+
+The LTest toolset is available in `opam`. More information [here](/fc-plugins/ltest.html).