BostonHousing data set URL needs to be updated.

[nandaleite]

Describe the bug
UCI ML Repository link http://mlr.cs.umass.edu/ml/datasets/housing is down and request of BostonHousing dataset is throwing an exception:

*** Exception: VanillaHttpException (HttpExceptionRequest Request {
  host                 = "mlr.cs.umass.edu"
  port                 = 80
  secure               = False
  requestHeaders       = []
  path                 = "/ml/machine-learning-databases/housing/housing.data"
  queryString          = ""
  method               = "GET"
  proxy                = Nothing
  rawBody              = False
  redirectCount        = 10
  responseTimeout      = ResponseTimeoutDefault
  requestVersion       = HTTP/1.1
  proxySecureMode      = ProxySecureWithConnect
}
 (ConnectionFailure Network.Socket.getAddrInfo (called with preferred socket type/protocol: AddrInfo {addrFlags = [], addrFamily = AF_UNSPEC, addrSocketType = Stream, addrProtocol = 0, addrAddress = 0.0.0.0:0, addrCanonName = Nothing}, host name: Just "mlr.cs.umass.edu", service name: Just "80"): does not exist (nodename nor servname provided, or not known)))

To Reproduce
Steps to reproduce the behavior:

1. On GHCi, type import Numeric.Datasets (getDataset)
2. Type import Numeric.Datasets.BostonHousing (bostonHousing)
3. Type bh <- getDataset bostonHousing
4. See error

Expected behavior
Loads the Boston Housing dataset into memory as the object bh.

Screenshots
N/A

Desktop (please complete the following information):

• OS: macOS
• GHC version 8.10.4

Smartphone (please complete the following information):
N/A

Additional context
Line below needs to be updated to use uciMLDB

dh-core/datasets/src/Numeric/Datasets/BostonHousing.hs

Line 64 in 2beb874

csvDataset $ URL $ umassMLDB /: "housing" /: "housing.data"

Reference: some data sets URLs corrected on #67

[ocramz]

Thanks @nandaleite for reporting! Could you submit a PR?