Ploomber

* Adds `ploomber nb --single-click/--single-click-disable` to enable/disable opening `.py` as notebooks with a click on Jupyter
* `ploomber nb` no longer requires a valid entry point if the selected option doesn't need one
* Better error message when `Pool` in the `Serial` executor raises `RuntimeError`
* Notebook static analysis: Better support for IPython magics, support for inline shell (`! echo hi`). closes [478](https://github.com/ploomber/ploomber/issues/478)

* Documents `S3Client` and `GCloudStorageClient`
* Updates to the telemetry module

* Fixes error message when failing to load dotted paths
* `ploomber scaffold` now supports `.R and .Rmd` files ([476](https://github.com/ploomber/ploomber/issues/476))
* Fixes an error that caused `ploomber scaffold` to ignore the location of existing packages ([459](https://github.com/ploomber/ploomber/issues/459))
* Better error message when running `ploomber execute/run` (suggests `ploomber build`)
* Better error message when passing positional arguments to `ploomber build` (suggests `ploomber task`)

* Fixes an error in the telemetry module

* Improved [anonymous user statistics](https://docs.ploomber.io/en/latest/community/user-stats.html)

* `PLOOMBER_STATS_ENABLED` environment variable can be used to disable stats
* Improved error message when a dotted path fails to load ([410](https://github.com/ploomber/ploomber/issues/410))