Require parent spans for database and HTTP

Changed

• Require parent spans on database and outgoing HTTP instrumentations that support it. When a database query is performed using the ioredis, pg, redis or mongoose libraries, or when an outgoing HTTP request is performed using the http module, a span will only be created if a trace has already been started in the current active context, that is, if the span to be created would have a parent.

  This helps prevent database queries and outgoing HTTP requests happening in uninstrumented contexts from counting towards your requests quota.

Fixed

• Add support for Koa v3.

View the Node.js package v3.7.4 changelog for more information.