User statistics endpoint returns lower case vault addresses, should return checksummed addresses.

[graham-u]

The /user/[address]/vaults/statistics endpoint returns results containing lower case vault addresses. This is in contrast to other endpoints that returned checksummed addresses.

This may require API users to have to process the results if their apps are expecting checksummed versions.

For consistency we should return checksummed addresses. This can be achieved simply with:

const checkSummedAddress = Web3.utils.toChecksumAddress(upperOrLowerCaseAddress);

Edit: A thought just occurred.. as small a change as this is, it could be a breaking change if anyone has come to rely on the addresses being lowercase. Unlikely but worth mentioning.