[xmlunit/xmlunit.net] 8e2df6: update build instructions

[Stefan B. <no...@gi...>]

  Branch: refs/heads/netstandard-2.0
  Home:   https://github.com/xmlunit/xmlunit.net
  Commit: 8e2df68d65eb55193c5fbad77a8ba26c062adddc
      https://github.com/xmlunit/xmlunit.net/commit/8e2df68d65eb55193c5fbad77a8ba26c062adddc
  Author: Stefan Bodewig <ste...@fr...>
  Date:   2019-04-04 (Thu, 04 Apr 2019)

  Changed paths:
    M README.md

  Log Message:
  -----------
  update build instructions