Update versions and changelog for release of v12.0.0a1

CHANGELOG/v12r0

+[v12.0.0a1]
+*ProductionManagement
+
+FIX: (!1467) added possibility to specify runs list for sprucing template
+
+*TransformationSystem
+
+FIX: (!1466) Follow Run 3 conditions database changes in checkRun3CondDB
+CHANGE: (!1461) be a bit more strict when comparing site names in the RAWReplicationBody
+CHANGE: (!1459) Skip debug directories in ValidateOutputDataAgent.
+
+*dashboards
+
+FIX: (!1464) the list of tier 2 sites is now queried from https://lhcb-portal-dirac.cern.ch/topology/topology.json
+
+
+