Change CONTRIBUTING to link to correct lang repos (#836)
Change CONTRIBUTING to link to correct lang repos (#836)

The URI changed for each language repo:
https://github.com/exercism/meta/issues/1

This PR changes the link in CONTRIBUTING.md to follow that convention
instead of relying on GH to redirect us.

kgengler/x-common,exercism/x-common,kgengler/x-common,exercism/x-common,Vankog/problem-specifications,petertseng/x-common,ErikSchierboom/x-common,petertseng/x-common,ErikSchierboom/x-common,jmluy/x-common,rpottsoh/x-common,rpottsoh/x-common,jmluy/x-common,jmluy/x-common,Vankog/problem-specifications