CONTRIBUTING.md in alba-2.1.0 vs CONTRIBUTING.md in alba-2.2.0

@@ -25,6 +25,6 @@
 * You should provide reason(s) behind your change unless it's so simple
 
 ## Documents
 
 * [code of conduct](https://github.com/okuramasafumi/alba/blob/master/CODE_OF_CONDUCT.md) for all contributors
-* [hacking document](https://github.com/okuramasafumi/alba/blob/master/DESIGN.md) for those who want to know the internal of Alba
+* [hacking document](https://github.com/okuramasafumi/alba/blob/main/HACKING.md) for those who want to know the internal of Alba