Fix Congo Free State franc starting date [Risolto]

Hello!

https://en.numista.com/catalogue/index.php?e=congo_belge&r=&st=1-2&cat=y&im1=&im2=&ru=&ie=&no=&v=&cu=&a=&dg=&i=&b=&m=&f=&t=&t2=&w=&mt=&u=&c=&wi=&sw=&o=v

The Congolese colonial franc started in 1887, not in 1885.

- Mambu ma Khenzu, E. (2003). A modern history of monetary and financial systems of Congo 1885-1995 [Doctoral dissertation, University of Greenwich]. Greenwich Academic Literature Archive. P. 64:

- National Bank of Belgium. Aperçu sur l'évolution de l'organisation monétaire et bancaire au Congo Belge. Bulletin d'Information et de Documentation 27, vol. 1, no. 6 (June 1952). P. 314:

Thanks, changed.