[xmlunit/xmlunit.net] f6e0b3: need to add submodules on Linux as well

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

  Branch: refs/heads/main
  Home:   https://github.com/xmlunit/xmlunit.net
  Commit: f6e0b3d6860decf6ce150fc8a15ddc574e17413f
      https://github.com/xmlunit/xmlunit.net/commit/f6e0b3d6860decf6ce150fc8a15ddc574e17413f
  Author: Stefan Bodewig <bo...@ap...>
  Date:   2023-03-14 (Tue, 14 Mar 2023)

  Changed paths:
    M appveyor.yml

  Log Message:
  -----------
  need to add submodules on Linux as well