Add skypeForConsumer as conferencing provider.#255

SubashPradhan merged 2 commits intomainnylas/nylas-java:mainfrom

CUST-3638-sdk-add-skype-for-consumer-conferencing-on-the-events-endpointnylas/nylas-java:CUST-3638-sdk-add-skype-for-consumer-conferencing-on-the-events-endpointCopy head branch name to clipboard