Remove use of boost::variant2
As it looks like the current version of ROOT (i.e. 6.24) no longer suffers from an allergy to std::variant
(see eg. Rec#124 (closed)), remove the workaround of using boost::variant2
instead of std::variant
. This is due to 6.24 using a newer version of llvm -- see eg. https://sft.its.cern.ch/jira/browse/ROOT-10220
Closes Rec#124 (closed)
Edited by Gerhard Raven