update sklearn calls to use latest API

Version 0.18 moved cross-validation to sklearn.model_selection - see https://scikit-learn.org/stable/whats_new.html#version-0-18
Version 0.17 deprecated class_weight="auto" in favor of class_weight="balanced"

examples/brewing-logreg.ipynb

@@ -73,7 +73,7 @@
  ")\n",
  "\n",
  "# Split into train and test\n",
- "X, Xt, y, yt = sklearn.cross_validation.train_test_split(X, y)\n",
+ "X, Xt, y, yt = sklearn.model_selection.train_test_split(X, y)\n",
  "\n",
  "# Visualize sample of the data\n",
  "ind = np.random.permutation(X.shape[0])[:1000]\n",
@@ -111,7 +111,7 @@
  "%%timeit\n",
  "# Train and test the scikit-learn SGD logistic regression.\n",
  "clf = sklearn.linear_model.SGDClassifier(\n",
- " loss='log', n_iter=1000, penalty='l2', alpha=5e-4, class_weight='auto')\n",
+ " loss='log', n_iter=1000, penalty='l2', alpha=5e-4, class_weight='balanced')\n",
  "\n",
  "clf.fit(X, y)\n",
  "yt_pred = clf.predict(Xt)\n",