MeetingMessageType typo

[AidaNow]

Hi,

I am using MeetingMessageType property in my code and I noticed that there is a typo in MeetingMessageType = 'MeetingTenativelyAccepted', where it should be 'MeetingTentativelyAccepted'

Reference: https://github.com/OfficeDev/Office-365-SDK-for-Java/blob/master/sdk/outlook-services/src/main/java/com/microsoft/services/outlook/MeetingMessageType.java

Please let me know if it is a valid concern.