Update file compress_dataset_without_enstools_write.ipynb

Update documentation following the suggestions from the article reviewers.

examples/notebooks/compress_dataset_without_enstools_write.ipynb

@@ -12,7 +12,8 @@
    "source": [
     "# Compress a Dataset without using enstools.io.write\n",
     "\n",
-    "An example on how to use the analyzer to analyze a **dataset** and use the results to store it in a compressed file"
+    "An example on how to use the analyzer to analyze a **dataset** and use the results to store it in a compressed file",
+    "Besides enstools-encoding, this example relies on **xarray**, **pooch** and **netCDF4** in order to use xarray's tutorial data."
    ]
   },
   {