Update to MacPorts 2.11.3

[ryandesign]

The infrastructure of the ports.macports.org web site appears to still be using a version of MacPorts earlier than 2.11.0, therefore when it encounters ports like x264 that use features introduced in MacPorts 2.11.0 it cannot parse the portfile and believes erroneously that the port doesn't exist. See https://trac.macports.org/ticket/72733. Please update the server's MacPorts to the latest version.