Remove build badge

It causes Check Links errors, possibly because CI can’t access private repo URLs?

Signed-off-by: Andy Jakubowski <hello@andyjakubowski.com>

Author: andyjakubowski

README.md

@@ -1,7 +1,5 @@
 # jupyterlab_deepnote
 
-[![Github Actions Status](https://github.com/deepnote/jupyterlab-deepnote/workflows/Build/badge.svg)](https://github.com/deepnote/jupyterlab-deepnote/actions/workflows/build.yml)
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 A Deepnote extension for JupyterLab
 
 This extension is composed of a Python package named `jupyterlab_deepnote`