Update links in CONTRIBUTING.md
Update links in CONTRIBUTING.md

Signed-off-by: Eric Stoekl <c868fdb6ebf54453af49164062f0c7f57f9b6c7f@gmail.com>

alexellis/faas,rgee0/faas,alexellis/faas,rgee0/faas,rgee0/faas,alexellis/faas,rgee0/faas,alexellis/faas,rgee0/faas,openfaas/faas,openfaas/faas,rgee0/faas,alexellis/faas,rgee0/faas,rgee0/faas,alexellis/faas,rgee0/faas,alexellis/faas,alexellis/faas,rgee0/faas,alexellis/faas,openfaas/faas