Grayskull

Fix recipe name when generating from a github repository.

- Generate recipes from Github repository
- Added information about how to generate recipe for GitHub repository packages.
- Add constrain for 3.6 in case it is --strict-conda-forge and it is noarch python
- Add Python 3.9 as part of python version conda-forge supports
- Small Improvements
- Replace slash in test imports by a dot
- Execute 'split' only if entry_point is a string
- Added check for scripts in metadata

Add fastjsonschema and flair to the configuration file to convert names on pypi to conda-forge

Invoke the same python when running pip

Moved grayskull to conda-incubator
Added Github Actions for the tests and also testing on OSX and Windows
Fix 194 - removed empty entry points
Fix version value appearing as unquoted jinja expression

Constrain ruamel.yaml and progressbar2