Update CHANGELOG.md from release 26.7.0 (#992)

Signed-off-by: Techassi <git@techassi.dev>

Author: Techassi

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+## [26.7.0] - 2026-07-21
+
+## [26.7.0-rc1] - 2026-07-16
+
 ### Added
 
 - BREAKING: Add required CLI argument and env var to set the image repository used to construct final product image names: `IMAGE_REPOSITORY` (`--image-repository`), eg. `oci.example.org/my/namespace` ([#961]).