Change Log: `Version` labels for current maintenance releases

[RealRaven2000]

Add a new pattern for whats-new-list to allow speedy creation of maintenance logs. This will be done via adding a maintenance class in a bold pseudo-tag containing the version number only - Example

{L}{b class=maintenance}6.12.3{/b} Fixed an issue where message preview was unavailable when moving mail to local folders [issue 364].{/L}

like this:

Objective: minimize amount of work when releasing important bug fixes and cognitive load for users