Fix link to lua example in readme

README.md

@@ -33,7 +33,7 @@ The easiest way to build against GTK Layer Shell is to use the `gtk-layer-shell-
 [examples/simple-example.py](examples/simple-example.py) contains sample Python code.
 
 ### Lua
-[examples/simple-example.py](examples/simple-example.py) contains sample Lua code. It uses [FFI](https://luajit.org/ext_ffi.html) which requires [LuaJIT](https://luajit.org/).
+[examples/simple-example.lua](examples/simple-example.lua) contains sample Lua code. It uses [FFI](https://luajit.org/ext_ffi.html) which requires [LuaJIT](https://luajit.org/).
 
 ### Vala
 [examples/simple-example.vala](examples/simple-example.vala) contains a minimal working Vala app.