Update the version of prettier being used

Update the version of prettier being used

Per https://github.com/prettier/prettier/issues/8925 prettier has
created a new pre-commit repository for pre-commit integration. This
repository also uses a slightly different tag format.

Lastly, we're updating to the latest version version available at this
time

Adds a .prettierignore to keep it from reformatting the
jenkins-init-scripts/README that shouldn't be touched

Change-Id: I0a50fc4fc372f43c6cd323aa1d6a2ec2054aeeda
Signed-off-by: Andrew Grimberg <agrimberg@linuxfoundation.org>