getMajorVersion
Returns the major version number of the libsoup library.
e.g. in libsoup version 2.42.0 this is 2.
This function is in the library, so it represents the libsoup library your code is running against. Contrast with the #SOUP_MAJOR_VERSION macro, which represents the major version of the libsoup headers you have included when compiling your code.
Return
the major version number of the libsoup library