tests: tell pip not to check for a newer version pip will check to see if it's the latest version, and complain if it isn't. The --no-index flag implies the --disable-pip-version-check flag, and makes the warning (and any associated network activity) go away.

changeset_templater: backport parts map of [templates] section from formatter

formatter: add support for parts map of [templates] section Unlike a mapfile whose template is looked up by spec -> mapfile -> topic, [templates] section is global. We use :sub-section syntax to define parts per template.