Release notes: fix markdown

When generating the release notes, add an empty line after
the "Cherry picks:" line, so that the enumeration of the
cherry-picked commits. In this way, the list is recognized
as a markdown enumeration.

Change-Id: I6ecca079411160fa84c08529703be5feffcfd43a
PiperOrigin-RevId: 212781946
diff --git a/scripts/release/common.sh b/scripts/release/common.sh
index 6563b2e..3df3e32 100755
--- a/scripts/release/common.sh
+++ b/scripts/release/common.sh
@@ -107,6 +107,7 @@
 # Baseline: BASELINE_COMMIT
 #
 # Cherry picks:
+#
 #    + CHERRY_PICK1: commit message summary of the CHERRY_PICK1. This
 #                    message will be wrapped into 70 columns.
 #    + CHERRY_PICK2: commit message summary of the CHERRY_PICK2.
@@ -117,6 +118,7 @@
   while [ -n "${1-}" ]; do
     if [[ "$first" -eq 1 ]]; then
       echo -e "\nCherry picks:"
+      echo
       first=0
     fi
     local hash="$(__git_commit_hash "${1}")"