message: Update nuget package to indicate that the c-callable SDK is required.
diff: <Authors>Symon Rottem</Authors>
  <Company>Hyperledger Indy</Company>
  <Product>Hyperledger Indy SDK</Product>
  - <Description>.NET wrapper for the Hyperledger Indy SDK</Description>
  + <Description>.NET wrapper for the Hyperledger Indy SDK.
  +
  +Please note that to function the C-Callable Hyperledger Indy SDK and its dependencies must be installed in the library/DLL search path - please see the project page for more information.</Description>
  <PackageProjectUrl>https://github.com/hyperledger/indy-sdk</PackageProjectUrl>
  <RepositoryUrl>https://github.com/hyperledger/indy-sdk</RepositoryUrl>
  <RepositoryType>git</RepositoryType>
  