Increase limit for azure blob from 64MB to 256MB

Since jclouds upgraded to use Azure API version 2017-04-17 it can also increase the limit for put blob from 64 MB to 256 MB as can be seen in Azure docs

https://docs.microsoft.com/en-us/rest/api/storageservices/understanding-block-blobs--append-blobs--and-page-blobs