Add string header to treeCreatorDstarSpinAlignMixing

Author: Mingze129

PWGHF/D2H/TableProducer/treeCreatorDstarSpinAlignMixing.cxx

@@ -47,6 +47,7 @@
 
 #include <cstdint>
 #include <vector>
+#include <string>
 
 using namespace o2;
 using namespace o2::framework;