changelog nest items belonging to 0.2.0

Signed-off-by: tarilabs <[email protected]>

CHANGELOG.md

@@ -14,8 +14,8 @@ and **Merged pull requests**. Critical items to know are:
 The versions coincide with releases on pip. Only major versions will be released as tags on Github.
 
 ## [0.0.x](https://github.com/oras-project/oras-py/tree/main) (0.0.x)
- - bugfix maintain requests's verify valorization for all invocations, augment basic auth header to existing headers (0.2.0)
  - refactor of auth to be provided by backend modules (0.2.0)
+   - bugfix maintain requests's verify valorization for all invocations, augment basic auth header to existing headers
  - Allow generating a Subject from a pre-existing Manifest (0.1.30)
  - add option to not refresh headers during the pushing flow, useful for push with basic auth (0.1.29)
  - enable additionalProperties in schema validation (0.1.28)