[openSUSE/obs-build] d4d7ac: Tweak multiline check

28 May 2021

      Branch: refs/heads/master
  Home:   https://github.com/openSUSE/obs-build
  Commit: d4d7ac7c06a7945eb2df22bc443afd371e05f8fc
      https://github.com/openSUSE/obs-build/commit/d4d7ac7c06a7945eb2df22bc443afd3...
  Author: Michael Schroeder <mls@suse.de>
  Date:   2021-05-28 (Fri, 28 May 2021)

  Changed paths:
    M Build/Rpm.pm

  Log Message:
  -----------
  Tweak multiline check

Unfortunately '$' also matches before a newline at the end of
the string, even if the /s modifier was used. So use \z to really
match the end of the string.