Bug#996201: Slack still can't be installed

[Gerardo Esteban Malazdrewicz]

I changed the Slack.deb control file to Depend on
libappindicator3-1 | libayatana-appindicator3-1 ( >= 0.5.90-6).

That allowed it to be installed, but if 0.5.90-6 adds compatilibity for
libappindicator3-1. maybe 0.5.90-7 can Provide it instead of Replacing it?

Thanks,
     Gerardo