Clarify v6 README (#2328)

Author: ericsciple

CHANGELOG.md

@@ -1,19 +1,19 @@
 # Changelog
 
-## V6.0.0
+## v6.0.0
 * Persist creds to a separate file by @ericsciple in https://github.com/actions/checkout/pull/2286
 * Update README to include Node.js 24 support details and requirements by @salmanmkc in https://github.com/actions/checkout/pull/2248
 
-## V5.0.1
+## v5.0.1
 * Port v6 cleanup to v5 by @ericsciple in https://github.com/actions/checkout/pull/2301
 
-## V5.0.0
+## v5.0.0
 * Update actions checkout to use node 24 by @salmanmkc in https://github.com/actions/checkout/pull/2226
 
-## V4.3.1
+## v4.3.1
 * Port v6 cleanup to v4 by @ericsciple in https://github.com/actions/checkout/pull/2305
 
-## V4.3.0
+## v4.3.0
 * docs: update README.md by @motss in https://github.com/actions/checkout/pull/1971
 * Add internal repos for checking out multiple repositories by @mouismail in https://github.com/actions/checkout/pull/1977
 * Documentation update - add recommended permissions to Readme by @benwells in https://github.com/actions/checkout/pull/2043

README.md

@@ -4,8 +4,9 @@
 
 ## What's new
 
-- Updated `persist-credentials` to store the credentials under `$RUNNER_TEMP` instead of directly in the local git config.
-  - This requires a minimum Actions Runner version of [v2.329.0](https://github.com/actions/runner/releases/tag/v2.329.0) to access the persisted credentials for [Docker container action](https://docs.github.com/en/actions/tutorials/use-containerized-services/create-a-docker-container-action) scenarios.
+- Improved credential security: `persist-credentials` now stores credentials in a separate file under `$RUNNER_TEMP` instead of directly in `.git/config`
+- No workflow changes required — `git fetch`, `git push`, etc. continue to work automatically
+- Running authenticated git commands from a [Docker container action](https://docs.github.com/actions/sharing-automations/creating-actions/creating-a-docker-container-action) requires Actions Runner [v2.329.0](https://github.com/actions/runner/releases/tag/v2.329.0) or later
 
 # Checkout v5