prepare the changelog for the 6.0.0 release (#1278)

* prepare the changelog for the 6.0.0 release

This includes a breaking change, so we should release a new major
version.

* Update CHANGELOG.md

Co-authored-by: Fitz <159924046+fitz-vivodyne@users.noreply.github.com>

* update date

---------

Co-authored-by: Fitz <159924046+fitz-vivodyne@users.noreply.github.com>

CHANGELOG.md

@@ -2,11 +2,13 @@
 
 ## HEAD (Unreleased)
 
-- feat: (breaking change) Update the `refresh` option to runcommands with the
- `--refresh` flag. ([#1118](https://github.com/pulumi/actions/pull/1118))
-
 ---
 
+## 6.0.0 (2024-09-27)
+
+- feat: (breaking change) Update the `refresh` option to run commands with the
+ `--refresh` flag. ([#1118](https://github.com/pulumi/actions/pull/1118))
+
 ## 5.5.1 (2024-08-23)
 
 - fix: `always-include-summary` only logs warning when ouput is too large