Move github.com/openzipkin/zipkin-go-opentracing => github.com/openzipkin-contrib/zipkin-go-opentracing (#3070)

Move github.com/openzipkin/zipkin-go-opentracing => github.com/openzipkin-contrib/zipkin-go-opentracing
and run `go mod tidy`

Fixes 3069
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>