Fix compilation error

Add missing include statement. Error shows up with FairSoft nov20 and
FairRoot v18.4.2. Refs #2036.

reco/detectors/sts/CbmStsFindTracksQa.h

@@ -15,10 +15,11 @@
 
 #include "CbmLink.h"
 
-#include "FairTask.h"
+#include <FairTask.h>
 
-#include "TStopwatch.h"
-#include "TVector3.h"
+#include <TFolder.h>
+#include <TStopwatch.h>
+#include <TVector3.h>
 
 class TH1F;
 class CbmMCDataArray;