Updating copyright string

[itsshivaverma]

So we can incorporate your pull request, please share the following:

• What issue are you addressing with this pull request?
  Copyright update to standard string
• Are you modifying the correct branch? (See CONTRIBUTING.md)
  Yes
• Have you run unit tests? (See CONTRIBUTING.md)
  NA
• Version of MarkLogic Java Client API (see Readme.txt)
  NA
• Version of MarkLogic Server (see admin gui on port 8001)
  NA
• Java version (java -version)
  NA
• OS and version
  NA
• What Changed: What happened before this change? What happens without this change?
  Its just a copyright update. Few years did not have correct copyright year, whereas most of the files copyright string was updated with the standard string.