bump sklearnserver rock to 0.11.2

[ca-scribner]

closes #35

Tester instructions

Launch the server with:

# download the model locally
gsutil cp -r gs://kfserving-examples/models/sklearn/1.0/model ./sample_model/

# mount the model into the container at runtime
docker run -p 8080:8080 -v $(pwd)/sample_model:/mnt/models sklearnserver:0.11.2 --model_name test_model --model_dir=/mnt/models --http_port=8080

Test the server with:

cat <<EOF >> iris-input-v2.json
{
  "inputs": [
    {
      "name": "input-0",
      "shape": [2, 4],
      "datatype": "FP32",
      "data": [
        [6.8, 2.8, 4.8, 1.4],
        [6.0, 3.4, 4.5, 1.6]
      ]
    }
  ]
}
EOF

curl -v \
  -H "Content-Type: application/json" \
  -d @./iris-input-v2.json \
  localhost:8080/v2/models/test_model/infer

[DnPlas]

Thanks @ca-scribner, super tiny little comment, other than that LGTM.

[DnPlas]

Same comment as here.

I think that this PR could be split in two just to unblock #35 and then we can move the discussion about the testing instructions elsewhere. wdyt?