Fix the link to the changelog spec

Author: baluyotraf

docs/customization.md

@@ -164,7 +164,7 @@ commitizen:
 | `change_type_map`   | `dict` | `None`  | (OPTIONAL) Dictionary mapping the type of the commit to a changelog entry                                                                                                                                                        |
 
 [jinja2]: https://jinja.palletsprojects.com/en/2.10.x/
-[changelog-spec]: https://commitizen-tools.github.io/commitizen/changelog/
+[changelog-spec]: https://commitizen-tools.github.io/commitizen/commands/changelog/
 
 #### Detailed `questions` content