Update Mu DevOps version to 15.0.3 (#461)

Includes:

- codeql: Use app token for API requests
- Use the GitHub app token for writing

---

Bumps the version for an upcoming release.

Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>

Author: makubacki

.sync/Version.njk

@@ -30,7 +30,7 @@
 #}
 
 {# The git ref value that files dependent on this repo will use. #}
-{% set mu_devops = "v15.0.2" %}
+{% set mu_devops = "v15.0.3" %}
 
 {# The latest Project Mu release branch value. #}
 {% set latest_mu_release_branch = "release/202502" %}