Update contrib/gem/README.md
Update contrib/gem/README.md

Fix a small typo.
waynr/puppetdb,highb/puppetdb,senior/puppetdb,github/puppetlabs-puppetdb,kbarber/puppetdb,senior/puppetdb,wkalt/puppetdb,mullr/puppetdb,jantman/puppetdb,grimradical/puppetdb,rbrw/puppetdb,wkalt/puppetdb,puppetlabs/puppetdb,grimradical/puppetdb,highb/puppetdb,wkalt/puppetdb,shrug/puppetdb,jantman/puppetdb,ajroetker/puppetdb,nfagerlund/puppetdb,puppetlabs/puppetdb,nfagerlund/puppetdb,ajroetker/puppetdb,cprice404/puppetdb,highb/puppetdb,mullr/puppetdb,senior/puppetdb,kbarber/puppetdb,waynr/puppetdb,shrug/puppetdb,johnduarte/puppetdb,johnduarte/puppetdb,cprice404/puppetdb,johnduarte/puppetdb,rbrw/puppetdb,melissa/puppetdb,mullr/puppetdb,puppetlabs/puppetdb,ajroetker/puppetdb,rbrw/puppetdb,rbrw/puppetdb,nfagerlund/puppetdb,kbrezina/puppetdb,shrug/puppetdb,johnduarte/puppetdb,shrug/puppetdb,kbrezina/puppetdb,puppetlabs/puppetdb,rbrw/puppetdb,puppetlabs/puppetdb,kbarber/puppetdb,melissa/puppetdb,waynr/puppetdb,kbrezina/puppetdb,jantman/puppetdb,cprice404/puppetdb,kbrezina/puppetdb,mullr/puppetdb,senior/puppetdb,waynr/puppetdb,wkalt/puppetdb,grimradical/puppetdb,github/puppetlabs-puppetdb,highb/puppetdb,kbarber/puppetdb,grimradical/puppetdb,melissa/puppetdb,github/puppetlabs-puppetdb,ajroetker/puppetdb,mullr/puppetdb