Prepare release 1.6.0 (jaegertracing#924)

* Prepare release 1.6.0

Signed-off-by: Yuri Shkuro <ys@uber.com>

* Add 1 more commit

Signed-off-by: Yuri Shkuro <ys@uber.com>

Preparing release 1.5.0 (jaegertracing#847)

Signed-off-by: Juraci Paixão Kröhling <juraci@kroehling.de>

Preparing release 1.4.1

Signed-off-by: Yuri Shkuro <ys@uber.com>

Prepare release 1.4.0 (jaegertracing#780)

Signed-off-by: Yuri Shkuro <ys@uber.com>

Prepare release 1.3.0 (jaegertracing#757)

Preparing release 1.2.0 (jaegertracing#689)

Signed-off-by: Yuri Shkuro <ys@uber.com>

Preparing release 1.1.0 (jaegertracing#612)

Signed-off-by: Yuri Shkuro <ys@uber.com>

Preparing release 1.0 (jaegertracing#580)

Preparing release 0.9.0 (jaegertracing#494)

Preparing release 0.8.0