adding a static_cast to fix a compile fail

Author: jjuracka

PWGUD/Tasks/upcRhoAnalysis.cxx

@@ -124,7 +124,7 @@ struct UpcRhoAnalysis {
 
   const float pcEtaCut = 0.9; // physics coordination recommendation
   const std::vector<int> runNumbers = {544013, 544028, 544032, 544091, 544095, 544098, 544116, 544121, 544122, 544123, 544124, 544184, 544185, 544389, 544390, 544391, 544392, 544451, 544454, 544474, 544475, 544476, 544477, 544490, 544491, 544492, 544508, 544510, 544511, 544512, 544514, 544515, 544518, 544548, 544549, 544550, 544551, 544564, 544565, 544567, 544568, 544580, 544582, 544583, 544585, 544614, 544640, 544652, 544653, 544672, 544674, 544692, 544693, 544694, 544696, 544739, 544742, 544754, 544767, 544794, 544795, 544797, 544813, 544868, 544886, 544887, 544896, 544911, 544913, 544914, 544917, 544931, 544947, 544961, 544963, 544964, 544968, 544991, 544992, 545004, 545008, 545009, 545041, 545042, 545044, 545047, 545060, 545062, 545063, 545064, 545066, 545086, 545103, 545117, 545171, 545184, 545185, 545210, 545222, 545223, 545246, 545249, 545262, 545289, 545291, 545294, 545295, 545296, 545311, 545312, 545332, 545345, 545367};
-  AxisSpec runNumberAxis = {runNumbers.size(), 0.5, static_cast<double>(runNumbers.size()) + 0.5, "run number"};
+  AxisSpec runNumberAxis = {static_cast<int>(runNumbers.size()), 0.5, static_cast<double>(runNumbers.size()) + 0.5, "run number"};
 
   Configurable<int> numPions{"numPions", 2, "required number of pions in the event"};