Minor update to contributing page
Minor update to contributing page

leonard84/spock,sebi-hgdata/spock,paplorinc/spock,sebi-hgdata/spock,psideleau/spock,spockframework/spock,GeeChao/spock,siordache/spock,raphw/spock,lokinell/spock,alien11689/spock,alien11689/spock,paplorinc/spock,lokinell/spock,sebi-hgdata/spock,psideleau/spock,lokinell/spock,GeeChao/spock,psideleau/spock,siordache/spock,siordache/spock,GeeChao/spock,paplorinc/spock,raphw/spock,alien11689/spock,raphw/spock