update erlang-esdl to 1.3.1

This is required for updating and unbreaking graphics/wings,
erlang-esdl's only consumer. (The current port's version is 1.0.1 is
10 years old, 1.3.1 is only 6 years old, and the whole thing has been
declared "legacy", but wings still requires it, so here we go). The
upstream maintainer has switched the build system from Makefiles to
rebar (rebar 2, rebar3 doesn't cut it) and made the former optional
dependencies on SDL-image and SDL-ttf mandatory.

esdl's former home at SourceForge has disappeared, the most current
version (even if it's not really current) is now available at Github,
WWW has been updated to reflect that change.

PR: 239173
Approved by: maintainer-timeout (erlang@)