Update README to mention two GAPIC APIs
Update README to mention two GAPIC APIs

Preview code for monitoring is copied from the autogenerated README.
VideoIntelligence does not have an autogenerated API sample, so code
is adapted from the autogen method sample (with fixes for
empty parameters).

CloudVLab/google-cloud-ruby,googleapis/google-cloud-ruby,dazuma/google-cloud-ruby,quartzmo/google-cloud-ruby,googleapis/google-cloud-ruby,landrito/google-cloud-ruby,blowmage/gcloud-ruby,CloudVLab/google-cloud-ruby,quartzmo/google-cloud-ruby,landrito/google-cloud-ruby,dazuma/google-cloud-ruby,qingling128/google-cloud-ruby,quartzmo/gcloud-ruby,dazuma/google-cloud-ruby,googleapis/google-cloud-ruby,quartzmo/google-cloud-ruby,quartzmo/google-cloud-ruby,quartzmo/google-cloud-ruby,CloudVLab/google-cloud-ruby,landrito/google-cloud-ruby,qingling128/google-cloud-ruby,CloudVLab/google-cloud-ruby,googleapis/google-cloud-ruby,dazuma/google-cloud-ruby,qingling128/google-cloud-ruby,landrito/google-cloud-ruby,qingling128/google-cloud-ruby,dazuma/google-cloud-ruby,googleapis/google-cloud-ruby,CloudVLab/google-cloud-ruby,landrito/google-cloud-ruby,googleapis/google-cloud-ruby,dazuma/google-cloud-ruby,quartzmo/google-cloud-ruby