Issue geerlingguy#2068: Update CHANGELOG for Drupal VM 6.0.0.

Issue geerlingguy#2025: Update Changelog for 5.2.0 release.

Issue geerlingguy#2015: Prepare for 5.1.1 release, drop CentOS 6 docu…

…mentation.

Issue geerlingguy#1994: Update CHANGELOG for 5.1.0 release [ci skip].

Issue geerlingguy#1986: Update CHANGELOG for 5.0.2 release.

Issue geerlingguy#1966: Changelog updates for 5.0.1.

Issue geerlingguy#1918: Update CHANGELOG for 5.0.0 release. [ci skip]

Issue geerlingguy#1882: Update CHANGELOG for Drupal VM 4.9.2 release.

One more CHANGELOG addition for 4.9.1. [ci skip]

Issue geerlingguy#1783: Use 'Creation of Tron' for 4.9.0 release name…

…. [ci skip]