docs/install: update with PyPI instructions

5 jobs for docs-install-pypi in 16 minutes and 15 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Test
passed flake8 #533895

00:03:59

passed integration #533898

00:06:20

passed pylint #533896

00:04:20

passed self #533899

00:16:14

passed unit #533897

00:05:15