title: How to init the pyproject.toml file
body: <p>I found that python can use pyproject.toml to list dependencies instead of requirements.txt file. It's more convenient and is very similar to package.json for node.However, I could not find a documentation to init the pyproject.toml file much like the  <code>npm init</code> command. How to autogenerate the file with virtualenv or pip?
  also, is there a way to autoupdate the toml file, as the packagaes get installed, much like npm --save tag, that saves the package to the package.json as its installed?</p>