Script to check changelog

.buildkite/check_changelog.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+#
+# this script is run by buildkite to check that a changelog file exists
+#
+set -e
+
+# we need 19.9 to read config from towncrier.toml
+pip3 install --pre 'towncrier>19.2'
+python3 -m towncrier.check