Allow overriding namespaces and other improvements

Changed

• Allow overriding namespaces that are automatically set by the AppSignal agent based on the OpenTelemetry instrumentation that emitted the span, such as the graphql or background namespaces.
• Log a debug message when the reported error is ignored by the ignore_errors config option.

Fixed

• Update mysql2 and pg instrumentations. This fixes an issue where queries performed using promises with mysql2@3.11.5 are not instrumented, as well as an issue where pg is not instrumented under certain bundlers and runtimes.

View the Node.js package v3.6.6 changelog for more information.