Fixing MegaLinter

Author: rliotino99

DPG/Tasks/AOTTrack/PID/HMPID/hmpidTableProducer.cxx

@@ -34,10 +34,9 @@
 #include <ReconstructionDataFormats/PID.h>
 #include <ReconstructionDataFormats/Track.h>
 #include <ReconstructionDataFormats/TrackParametrization.h>
-
 #include <TTree.h>
-
 #include <string>
+#include <unordered_set>
 
 using namespace o2;
 using namespace o2::framework;