Fix some errata

README.md

- install most of these of these => install most of these
- a two more commands need to be => two more commands need to be
- This incurs a second issue in that downstream jobs that depend on the
  existence of some data that does not yet exist because another worker has not
  yet committed it's data.
    =>
  This incurs a second issue in that downstream jobs depend on the existence of
  some data that does not yet exist because another worker has not yet committed
  its data.