Fix sample in README

[xgouchet]

What does this PR do?

Updates the sample in Readme file to reflect the current API

[codecov-commenter]

Codecov Report

Merging #1141 (f19fc3e) into develop (b41e46f) will decrease coverage by 0.10%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #1141      +/-   ##
===========================================
- Coverage    83.17%   83.08%   -0.10%     
===========================================
  Files          274      274              
  Lines         9462     9462              
  Branches      1540     1540              
===========================================
- Hits          7870     7861       -9     
- Misses        1152     1162      +10     
+ Partials       440      439       -1     

Impacted Files	Coverage Δ
...android/log/internal/logger/TelemetryLogHandler.kt	75.00% <0.00%> (-25.00%)	⬇️
...android/rum/internal/ndk/DatadogNdkCrashHandler.kt	84.86% <0.00%> (-2.70%)	⬇️
...ndroid/telemetry/internal/TelemetryEventHandler.kt	69.64% <0.00%> (-2.68%)	⬇️
...rc/main/java/com/datadog/opentracing/DDTracer.java	55.65% <0.00%> (-0.42%)	⬇️
.../android/rum/internal/monitor/DatadogRumMonitor.kt	92.78% <0.00%> (ø)
...ain/java/com/datadog/opentracing/PendingTrace.java	58.62% <0.00%> (+0.86%)	⬆️