chore: add changelog for release 0.3.0 [ENG-5592] (#104)

[ENG-5592](https://stacklet.atlassian.net/browse/ENG-5592)

### what

add changelog entries for the release

### why

prepare release

### testing

n/a

### docs

n/a


[ENG-5592]:
https://stacklet.atlassian.net/browse/ENG-5592?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

Author: albertodonato

CHANGELOG.md

@@ -1,3 +1,23 @@
+## 0.3.0 - 2025-08-26
+
+- Add module versions for `stacklet_platform` data source.
+- Add support for the following resource types:
+  * `stacklet_configuration_profile_account_owners`
+  * `stacklet_configuration_profile_resource_owner`
+  * `stacklet_notification_template`
+  * `stacklet_report_group`
+- Add support for the following data source types:
+  * `stacklet_configuration_profile_account_owners`
+  * `stacklet_configuration_profile_email`
+  * `stacklet_configuration_profile_jira`
+  * `stacklet_configuration_profile_resource_owner`
+  * `stacklet_configuration_profile_servicenow`
+  * `stacklet_configuration_profile_slack`
+  * `stacklet_configuration_profile_symphony`
+  * `stacklet_configuration_profile_teams`
+  * `stacklet_notification_template`
+  * `stacklet_report_group`
+
 ## 0.2.0 - 2025-07-02
 
 - Add `stacklet_platform` data source.