Fix indentation in releasenotes

This commit fixes indentations in releasenotes. Due to the indentations,
the html contents are rendered as block quotes which is awkward.

Change-Id: Ia9f271ead6a6e3fb90afc935771e8da4d8990c3c
diff --git a/releasenotes/notes/tempest-stein-release-18bad34136a2e6ef.yaml b/releasenotes/notes/tempest-stein-release-18bad34136a2e6ef.yaml
index 212cf7d..c3537fc 100644
--- a/releasenotes/notes/tempest-stein-release-18bad34136a2e6ef.yaml
+++ b/releasenotes/notes/tempest-stein-release-18bad34136a2e6ef.yaml
@@ -1,14 +1,14 @@
 ---
-prelude: >
+prelude: |
     This release is to tag the Tempest for OpenStack Stein release.
     This release marks the start of Stein release support in Tempest and
     the end of support for Ocata in Tempest.
     After this release, Tempest will support below OpenStack Releases:
 
-      * Stein
-      * Rocky
-      * Queens
-      * Pike
+    * Stein
+    * Rocky
+    * Queens
+    * Pike
 
     Current development of Tempest is for OpenStack Train development
     cycle. Every Tempest commit is also tested against master during