(MODULES-3491) Describe version strategy in README
(MODULES-3491) Describe version strategy in README

This commit documents the version strategy used to determine a version number
when releasing the module.  This commit also removes trailing whitespace.

[ci skip]

ConclusionMC/puppetlabs-dsc,Iristyle/puppetlabs-dsc,ConclusionMC/puppetlabs-dsc,ferventcoder/puppetlabs-dsc,ConclusionMC/puppetlabs-dsc,Iristyle/puppetlabs-dsc,jpogran/puppetlabs-dsc,puppetlabs/puppetlabs-dsc,jpogran/puppetlabs-dsc,ferventcoder/puppetlabs-dsc,ConclusionMC/puppetlabs-dsc,puppetlabs/puppetlabs-dsc,ferventcoder/puppetlabs-dsc,puppetlabs/puppetlabs-dsc,ferventcoder/puppetlabs-dsc,Iristyle/puppetlabs-dsc,Iristyle/puppetlabs-dsc,jpogran/puppetlabs-dsc,ConclusionMC/puppetlabs-dsc