Merge topic 'FindProtobuf-upstream-options'

f784ef75a7 FindProtobuf: Add documentation for protobuf_generate()
cd3ff53c88 FindProtobuf: Add DEPENDENCIES to protobuf_generate
31adc11030 FindProtobuf: Add PLUGIN_OPTIONS and PROTOC_OPTIONS to protobuf_generate

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Merge-request: !8601