(PDB-3123) Update release notes for 4.2.4
(PDB-3123) Update release notes for 4.2.4

rbrw/puppetdb,mullr/puppetdb,puppetlabs/puppetdb,waynr/puppetdb,waynr/puppetdb,mullr/puppetdb,senior/puppetdb,senior/puppetdb,rbrw/puppetdb,rbrw/puppetdb,rbrw/puppetdb,mullr/puppetdb,waynr/puppetdb,puppetlabs/puppetdb,puppetlabs/puppetdb,waynr/puppetdb,senior/puppetdb,puppetlabs/puppetdb,mullr/puppetdb,rbrw/puppetdb,senior/puppetdb,mullr/puppetdb,puppetlabs/puppetdb