sqlite: __delitem__: use 0 instead of False

Leftover from #8

src/sqltrie/sqlite/sqlite.py

@@ -213,7 +213,7 @@ def __delitem__(self, key):
         node = self._get_node(key)
         self._conn.execute(
             """
-            UPDATE nodes SET has_value = False, value = NULL WHERE id == ?
+            UPDATE nodes SET has_value = 0, value = NULL WHERE id == ?
             """,
             (node["id"],),
         )