Add changelog entries for 1.7.0 and 1.8.0 (#33)

Author: mondeja

CHANGELOG.md

@@ -7,6 +7,14 @@ All notable changes to this project will be documented in this file.
 - Fix reference clashing for options which only differ between upper and lower case
 - Do not render default values for `store_true` and `store_false` actions
 
+## 1.8.0
+
+- Support Python 3.10
+
+## 1.7.0
+
+- Support for adding custom subsection group title prefix (`group_title_prefix` and `group_sub_title_prefix` directive arguments)
+
 ## 1.6.0 (2021-04-15)
 
 - Support for using the `ref` sphinx role to refer to all anchor-able objects generated by the tool