Fix typo. (#8192)

Author: trivialfis

python-package/MANIFEST.in

@@ -18,7 +18,7 @@ recursive-include xgboost/include *
 recursive-include xgboost/plugin *
 recursive-include xgboost/src *
 
-recursive-include xgboost/gputreeshap/GPUTreeshap *
+recursive-include xgboost/gputreeshap/GPUTreeShap *
 
 include xgboost/rabit/CMakeLists.txt
 recursive-include xgboost/rabit/include *