Pin microshift build for openshift-4.15 4.15.39 (#5714)

Created by job run https://art-jenkins.apps.prod-stable-spoke1-dc-iad2.itup.redhat.com/job/aos-cd-builds/job/build%252Fbuild-microshift/1399

Co-authored-by: AOS Automation Release Team <noreply@redhat.com>

releases.yml

@@ -24,7 +24,12 @@ releases:
             non_gc_tag: "rhaos-4.15-ironic-rhel-9"
       members:
         images: []
-        rpms: []
+        rpms:
+        - distgit_key: microshift
+          why: Pin microshift to assembly
+          metadata:
+            is:
+              el9: microshift-4.15.39-202411211516.p0.gf64726d.assembly.4.15.39.el9
       rhcos:
         machine-os-content:
           images: