fix: make logger property public instead of private in BasicTracer

[mayurkale22]

Which problem is this PR solving?

• Fixes Make logger property public instead of private in BasicTracer class #211

Short description of the changes

• The Logger is private property in BasicTracer class, in current scenario we have to pass logger everywhere. Making it public solves this problem.

[mayurkale22]

/cc @OlivierAlbertini

[OlivierAlbertini]

awesome!

[codecov-io]

Codecov Report

Merging #213 into master will increase coverage by 0.3%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master     #213     +/-   ##
=========================================
+ Coverage   93.92%   94.22%   +0.3%     
=========================================
  Files          47       48      +1     
  Lines        1645     1750    +105     
  Branches      109      118      +9     
=========================================
+ Hits         1545     1649    +104     
- Misses        100      101      +1

Impacted Files	Coverage Δ
packages/opentelemetry-basic-tracer/src/Span.ts	100% <100%> (ø)	⬆️
...ages/opentelemetry-basic-tracer/src/BasicTracer.ts	98.14% <100%> (ø)	⬆️
...kages/opentelemetry-basic-tracer/test/Span.test.ts	100% <100%> (ø)	⬆️
...ckages/opentelemetry-core/src/common/NoopLogger.ts	14.28% <0%> (-5.72%)	⬇️
...s/opentelemetry-core/test/trace/tracestate.test.ts	100% <0%> (ø)	⬆️
...lemetry-core/test/trace/ProbabilitySampler.test.ts	100% <0%> (ø)	⬆️
.../opentelemetry-core/src/trace/spancontext-utils.ts	100% <0%> (ø)	⬆️
...s/opentelemetry-core/test/trace/NoopTracer.test.ts	100% <0%> (ø)	⬆️
...ckages/opentelemetry-core/test/platform/id.test.ts	100% <0%> (ø)	⬆️
... and 11 more