1.0 Release plan

[mensfeld]

This lib is stable for a while now.

With precompiled extensions, there are onlya few things that we should tackle before 1.0:

• Create spec that will check features available in the librdkafka runtime post-compile #696
• Setup the kafka warning detection post CI script #685
• Make glibc incompatibility error more descriptive #654
• Key partitioner is using #size instead of bytesize potentially causing incorrect partition assignments #629
• Verify that native extensions are not compiled for precompiled gems #644
• Use independent spec topics #621
• Support rd_kafka_ListOffsets #613
• Switch to the Data object for messages rdkafka #596
• Improve YARD docs quality #274
• feat: reporting client software name and version to broker #269
• Subscribe to topic partition list #233

once those are done we can craft 1.0.