net/miniupnpc: update to version 2.1

Changes:

VERSION 2.1 : released 2018/05/07

2018/05/07:
  CMake Modernize and cleanup CMakeLists.txt
  Update MS Visual Studio projects

2018/04/30:
  listdevices: show devices sorted by XML desc URL

2018/04/26:
  Small fix in miniupnpcmodule.c (python module)
  Support cross compiling in Makefile.mingw

2018/04/06:
  Use SOCKET type instead of int (for Win64 compilation)
  Increments API_VERSION to 17

2018/02/22:
  Disable usage of MiniSSDPd when using -m option

2017/12/11:
  Fix buffer over run in minixml.c
  Fix uninitialized variable access in upnpreplyparse.c

2017/05/05:
  Fix CVE-2017-8798  Thanks to tin/Team OSTStrom

2016/11/11:
  check strlen before memcmp in XML parsing portlistingparse.c
  fix build under SOLARIS and CYGWIN

2016/10/11:
  Add python 3 compatibility to IGD test

(nia)