Update CODEOWNERS to include more contributors

Added additional owners for the PWGEM path.

Author: dsekihat

CODEOWNERS

@@ -29,7 +29,7 @@
 /EventFiltering/PWGCF @alibuild @lauraser @mpuccio @lietava @fgrosa @ariedel-cern
 /EventFiltering/PWGMM @alibuild @aortizve @mpuccio @lietava @fgrosa @ariedel-cern
 /EventFiltering/PWGJE @alibuild @fkrizek @nzardosh @mpuccio @lietava @fgrosa @ariedel-cern
-/EventFiltering/PWGEM @alibuild @dsekihat @nstrangm
+/EventFiltering/PWGEM @alibuild @dsekihat @nstrangm @mpuccio @lietava @fgrosa @ariedel-cern
 
 /PWGCF               @alibuild @victor-gonzalez @zchochul @lgraczykCern @prchakra @lauraser @ariedel-cern @EmilGorm @otonvd @shouqiye @glromane
 /PWGCF/Core          @alibuild @jgrosseo @victor-gonzalez @zchochul @lgraczykCern @prchakra @lauraser @ariedel-cern @EmilGorm @otonvd @shouqiye @glromane