Add "Open in Colab" in quickstart guide.
"\n",
"# Acme quickstart guide\n",
"\n",
+ "[![Open in Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/deepmind/acme/blob/master/examples/quickstart.ipynb)\n",
+ "\n",
"This tutorial will walk you through how to construct a basic agent in Acme, define an environment to run that agent in, and finally to define the network architecture that acts as the *glue* between the agent and the environment.\n",
"\n",
"To make running experiments as easy as possible, Acme provides a high level\n",
