Update example notebook for master -> main rename

Addresses #76.

Author: pont-us

examples/notebooks/Ex0-CDS-store-setup.ipynb

@@ -10,7 +10,7 @@
     "\n",
     "### Installation\n",
     "\n",
-    "To installing the `xcube_cds` plugin follow the instructions given in the [xcube-cds README](https://github.com/dcs4cop/xcube-cds/blob/master/README.md).\n",
+    "To install the `xcube_cds` plugin follow the instructions given in the [xcube-cds README](https://github.com/dcs4cop/xcube-cds/blob/main/README.md).\n",
     "\n",
     "Before using Jupyter Lab for the first time, install the `jupyterlab` package and the `nodejs` package, and make sure the \n",
     "[Jupyter GeoJSON extension](https://www.npmjs.com/package/@jupyterlab/geojson-extension) is installed too:\n",