Update https://git.code.sf.net/p/libpng/code from 1.6.35 to 1.6.37
Update https://git.code.sf.net/p/libpng/code from 1.6.35 to 1.6.37

gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab