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

Preparing release 0.7.0 (jaegertracing#351)

Preparing release 0.6.0 (jaegertracing#328)

Preparing release 0.5.2

Preparing release 0.5.1

Add changelog