fix: Resolve link error in PythonQtTestMain on Windows

This changes the type of the `argv` parameter in the `main` function
to match the expected signature for integration with the CMake testing
framework. By default, the test driver expects the main function to have
the following signature:

```
typedef int (*MainFuncPointer)(int, char* []);
```

See https://github.com/Kitware/CMake/blob/master/Templates/TestDriver.cxx.in

This fixes a link error when building PythonQtCppTests on Windows:

```
1>PythonQtCppTests.obj : error LNK2001: unresolved external symbol "int __cdecl tests_PythonQtTestMain(int,char * * const)" (?tests_PythonQtTestMain@@YAHHQEAPEAD@Z)
1>C:\temp\PythonQt-build\Debug\PythonQtCppTests.exe : fatal error LNK1120: 1 unresolved externals
```

(cherry picked from commit commontk/PythonQt@aa1a16f)

Author: msmolens

tests/PythonQtTestMain.cpp

@@ -45,7 +45,7 @@
 
 #include <QApplication>
 
-int main( int argc, char **argv )
+int main(int argc, char *argv[])
 {
   QApplication qapp(argc, argv);