Update CODEOWNERS for PWGEM

Add Joshua as new PWGEM convener to the PWGEM code owner

Author: mhemmer-cern

CODEOWNERS

@@ -36,9 +36,9 @@
 /PWGCF/TableProducer @alibuild @jgrosseo @victor-gonzalez @zchochul @lgraczykCern @prchakra @lauraser @ariedel-cern @EmilGorm @otonvd @shouqiye @glromane
 /PWGCF/Tasks         @alibuild @jgrosseo @victor-gonzalez @zchochul @lgraczykCern @prchakra @lauraser @ariedel-cern @EmilGorm @otonvd @shouqiye @glromane
 /PWGDQ @alibuild @iarsene @mcoquet642 @lucamicheletti93 @XiaozhiBai
-/PWGEM @alibuild @feisenhu @dsekihat @ivorobye
-/PWGEM/Dilepton @alibuild @mikesas @rbailhac @dsekihat @ivorobye @feisenhu @hscheid
-/PWGEM/PhotonMeson @alibuild @mikesas @rbailhac @m-c-danisch @novitzky @mhemmer-cern @dsekihat
+/PWGEM @alibuild @feisenhu @dsekihat @ivorobye @jokonig
+/PWGEM/Dilepton @alibuild @mikesas @rbailhac @dsekihat @ivorobye @feisenhu @hscheid @jokonig
+/PWGEM/PhotonMeson @alibuild @mikesas @rbailhac @m-c-danisch @novitzky @mhemmer-cern @dsekihat @jokonig
 /PWGHF @alibuild @vkucera @fcolamar @fgrosa @fcatalan92 @mfaggin @mmazzilli @deepathoms @NicoleBastid @hahassan7 @jpxrk @apalasciano @zhangbiao-phy @gluparel @stefanopolitano @xinyepeng
 # PWG-LF
 /PWGLF @alibuild @sustripathy @skundu692 @mpuccio