docs: clarify V6 ESM migration is not a user-facing breaking change (#1090)

* docs: clarify V6 ESM migration is not a user-facing breaking change

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

* Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

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Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: 3 people

README.md

@@ -18,9 +18,9 @@ The `setup-java` action provides the following functionality for GitHub Actions
 
 This action allows you to work with Java and Scala projects.
 
-## Breaking changes in V6
+## What's new in V6
 
-- **Migrated to ESM** to enable support for the latest `@actions/*` package versions.
+- **Migrated to ESM** to enable support for the latest `@actions/*` package versions. This is an internal implementation change only. No changes are required to your workflow configuration, and the action's behavior is unchanged. Existing workflows continue to work as before.
 
 ## Breaking changes in V5