update proto files from 0.20.0 release
update proto files from 0.20.0 release

mdevilliers/erlang-mesos,basho-labs/mesos-executor-bindings,mokele/erlang-mesos,basho-labs/erlang-mesos,basho-labs/erlang-mesos,mokele/erlang-mesos,mdevilliers/erlang-mesos,basho-labs/mesos-executor-bindings