Merge branch 'fforster/service-name' into 'master'

fix(tracing): Add the `service.name` default attribute in the Stackdriver tracer.

See merge request !234



Merged-by: Steve Xuereb <sxuereb@gitlab.com>
Approved-by: Steve Xuereb <sxuereb@gitlab.com>
Co-authored-by: Florian Forster <fforster@gitlab.com>