Update Stackdriver exporter example

[mayurkale22]

Which problem is this PR solving?

• Based on 0.3.3 release.

/cc @dyladan

[codecov-io]

Codecov Report

Merging #731 into master will increase coverage by 5.38%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #731      +/-   ##
==========================================
+ Coverage   90.93%   96.32%   +5.38%     
==========================================
  Files         225      198      -27     
  Lines       10351     9170    -1181     
  Branches      953      787     -166     
==========================================
- Hits         9413     8833     -580     
+ Misses        938      337     -601

Impacted Files	Coverage Δ
...ckages/opentelemetry-core/src/common/NoopLogger.ts	33.33% <0%> (-16.67%)	⬇️
...metry-core/src/trace/instrumentation/BasePlugin.ts	81.57% <0%> (-5.27%)	⬇️
packages/opentelemetry-plugin-mysql/src/utils.ts	90.9% <0%> (-4.55%)	⬇️
...core/src/context/propagation/BinaryTraceContext.ts	97.5% <0%> (-0.84%)	⬇️
packages/opentelemetry-plugin-dns/src/version.ts	100% <0%> (ø)	⬆️
...opentelemetry-base/test/resources/resource.test.ts	100% <0%> (ø)	⬆️
...entelemetry-exporter-jaeger/test/transform.test.ts	100% <0%> (ø)	⬆️
packages/opentelemetry-tracing/src/config.ts	100% <0%> (ø)	⬆️
packages/opentelemetry-tracing/src/utility.ts	100% <0%> (ø)	⬆️
...ges/opentelemetry-exporter-zipkin/src/transform.ts	100% <0%> (ø)	⬆️
... and 72 more