chore: upgrade ts-node version to ^8.6.2

[mayurkale22]

Which problem is this PR solving?

• ts-node old versions is no longer work on Node V8, because yn is enforcing Node V10 compatibility. Caused by: https://github.com/sindresorhus/yn/pull/266

[dyladan]

Like that this makes the versions consistent too. Looks like it was all over the place before.

[codecov-io]

Codecov Report

Merging #687 into master will decrease coverage by 1.97%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master    #687      +/-   ##
=========================================
- Coverage   91.58%   89.6%   -1.98%     
=========================================
  Files         217     213       -4     
  Lines       10156   10038     -118     
  Branches      916     931      +15     
=========================================
- Hits         9301    8995     -306     
- Misses        855    1043     +188

Impacted Files	Coverage Δ
packages/opentelemetry-core/test/utils/url.test.ts	50% <0%> (-50%)	⬇️
...pentelemetry-core/test/internal/validators.test.ts	50% <0%> (-50%)	⬇️
...elemetry-core/test/trace/spancontext-utils.test.ts	55.55% <0%> (-44.45%)	⬇️
...lemetry-core/test/trace/ProbabilitySampler.test.ts	56.52% <0%> (-43.48%)	⬇️
...s/opentelemetry-core/test/trace/NoopTracer.test.ts	60% <0%> (-40%)	⬇️
...s/opentelemetry-core/test/context/B3Format.test.ts	63.39% <0%> (-36.61%)	⬇️
...ges/opentelemetry-core/test/trace/NoopSpan.test.ts	63.63% <0%> (-36.37%)	⬇️
...s/opentelemetry-core/test/trace/tracestate.test.ts	65.06% <0%> (-34.94%)	⬇️
...ntelemetry-core/test/trace/NoRecordingSpan.test.ts	71.42% <0%> (-28.58%)	⬇️
...ackages/opentelemetry-core/src/platform/node/id.ts	71.42% <0%> (-28.58%)	⬇️
... and 50 more