[DOC] Update link in minirocket.ipynb (#4577)

One of the links in the MiniRocket notebook was pointing at a file that
doesn't seem to exist, and I found one that is similarly named and seems
to have relevant content.

examples/minirocket.ipynb

@@ -69,7 +69,7 @@
    "source": [
     "### 1.2 Load the Training Data\n",
     "\n",
-    "For more details on the data set, see the [univariate time series classification notebook](https://github.com/sktime/sktime/blob/main/examples/02_classification_univariate.ipynb).\n",
+    "For more details on the data set, see the [univariate time series classification notebook](https://github.com/sktime/sktime/blob/main/examples/02_classification.ipynb).\n",
     "\n",
     "**Note**: Input time series must be *at least* of length 9.  Pad shorter time series using, e.g., `PaddingTransformer` (`sktime.transformers.panel.padder`)."
    ]