add npmrc for stricter install saving (#3851)
add npmrc for stricter install saving (#3851)

- save-exact=true
flodolo/testpilot,flodolo/testpilot,mozilla/idea-town-server,mozilla/idea-town-server,flodolo/testpilot,mozilla/idea-town,mozilla/idea-town,mozilla/idea-town-server,flodolo/testpilot,mozilla/idea-town,mozilla/idea-town-server,mozilla/idea-town