Add libxlsxwriter topic to the GitHub project metadata

[jmcnamara]

Hi,

Could you add libxlsxwriter as a "topic" metadata to your project so that users can find wrappers in different languages.

Topic/Metadata are shown at the top of the project: https://github.com/jmcnamara/libxlsxwriter

Other examples: https://github.com/search?q=topic%3Alibxlsxwriter&type=Repositories

I'll probably add a section on language wrappings to the libxlsxwriter documentation.

Thanks,

John

[KeepCoolWithCoolidge]

Added.

[jmcnamara]

Thank you!