add header

Author: kumaraditya303

Modules/_json.c

@@ -10,6 +10,7 @@
 
 #include "Python.h"
 #include "pycore_ceval.h"         // _Py_EnterRecursiveCall()
+#include "pycore_critical_section.h" // Py_BEGIN_CRITICAL_SECTION_SEQUENCE_FAST()
 #include "pycore_global_strings.h" // _Py_ID()
 #include "pycore_pyerrors.h"      // _PyErr_FormatNote
 #include "pycore_runtime.h"       // _PyRuntime