[ruby-cvs:71368] k0kubun:r64276 (trunk): appveyor.yml: don't notify PR failure to Slack

[k0kubun at ruby-lang.org]

k0kubun	2018-08-10 21:55:18 +0900 (Fri, 10 Aug 2018)

  New Revision: 64276

  https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=64276

  Log:
    appveyor.yml: don't notify PR failure to Slack

  Modified files:
    trunk/appveyor.yml