Update changelog for v1.0.0

Author: tarleb

changelog.md

@@ -1,13 +1,29 @@
 # hslua-aeson
 
+## v1.0.0
+
+- Update to hslua 1.0.0
+
+- Function `registerNull` has been replaced by `pushNull`.
+
+ Using `pushNull` has the advantage that users won't have to remember
+ to register a special variable. Users who need a global variable can
+ set it by running
+
+  pushNull
+  setglobal "HSLUA_AESON_NULL"
+
+
 ## v0.3.0
 
 - Update to hslua 0.8.0.
 
+
 ## v0.2.0
 
 - Update to hslua 0.6.0.
 
+
 ## v0.1.0.4
 
 - Ensure compatibility with hslua 0.5.0.