Koji 1.27 release notes

Fixes: https://pagure.io/koji/issue/3127

docs/source/migrations/migrating_to_1.27.rst

@@ -0,0 +1,15 @@
+Migrating to Koji 1.27
+======================
+
+You should consider the following changes when migrating to 1.27:
+
+DB Updates
+----------
+
+This release doesn't include any schema change.
+
+Other changes
+-------------
+
+There are numerous other changes in 1.27 that should not have a direct impact on migration. For
+details see: :doc:`../release_notes/release_notes_1.27`

docs/source/migrations/migrations.rst

@@ -5,6 +5,7 @@ Migrations
 .. toctree::
     :maxdepth: 1
 
+    migrating_to_1.27
     migrating_to_1.26
     migrating_to_1.25
     migrating_to_1.24