Avoid paging issues for git log messages (#1316)

Author: mrodm

.buildkite/hooks/post-checkout

@@ -47,7 +47,7 @@ MERGE_BRANCH="pr_merge_${PR_ID}"
 checkout_merge "${TARGET_BRANCH}" "${PR_COMMIT}" "${MERGE_BRANCH}"
 
 echo "Commit information"
-git log --format=%B -n 1
+git --no-pager log --format=%B -n 1
 
 # Ensure buildkite groups are rendered
 echo ""