Add ability to subscribe to table updates.

This was implemented based on
[this](https://www.sqlite.org/c3ref/update_hook.html) document.

src/esqlite3_nif.erl

@@ -23,6 +23,7 @@
 %% low-level exports
 -export([start/0,
          open/4,
+         set_update_hook/4,
          exec/4,
          changes/3,
          insert/4,
@@ -62,6 +63,9 @@ start() ->
 open(_Db, _Ref, _Dest, _Filename) ->
     erlang:nif_error(nif_library_not_loaded).
 
+set_update_hook(_Db, _Ref, _Dest, _Pid) ->
+    erlang:nif_error(nif_library_not_loaded).
+
 %% @doc Exec the query.
 %%
 %% Sends an asynchronous exec command over the connection and returns