Pull sampling probability from env var `OTEL_TRACES_SAMPLER_ARG` in the default sdk config (#737)
Pull sampling probability from env var `OTEL_TRACES_SAMPLER_ARG` in the default sdk config (#737)

Signed-off-by: jbtrystram <2a64d2384370d3a99f70d1bb9b527fa9908532fd@redhat.com>
open-telemetry/opentelemetry-rust,open-telemetry/opentelemetry-rust