Add "Launch in Deepnote" button

[danzvara]

Hi there, I'm Dan from Deepnote. We're a small startup working on a new, jupyter-compatible data science notebook. I was trying out Deepnote with some cool public repos like this one and I thought it might be useful for others too to have a one-click button to run your repo, so I submitted a PR.
Hope you find it useful!

Thanks for your work,
Dan

[graykode]

Thanks for your contribution! but we already have used google colab!