Add link to asynchronous version of Conway's Game of Life

Author: lemmy

specifications/GameOfLife/README.md

@@ -2,4 +2,6 @@ GameOfLife.tla
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 [Conway's Game of Life](https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life)
-This specification with some more description can be also found [here](https://github.com/mryndzionek/tlaplus_specs#gameoflifetla)
+This specification with some more description can be also found [here](https://github.com/mryndzionek/tlaplus_specs#gameoflifetla).
+
+A model of an asynchronous version of Conway's Game of Life, inspired by Chrystopher L. Nehaniv's work, "Evolution in Asynchronous Cellular Automata," is available at https://github.com/lemmy/AsyncGameOfLife/blob/master/AsyncGameOfLife.tla.