slack notifications

[dannylamb]

Github Issue: Islandora/documentation#1317

What does this Pull Request do?

Adds slack notifications to Travis.

How should this be tested?

The build status from this PR should get spammed to #notifications in slack.

Interested parties

@Islandora/8-x-committers

[codecov]

Codecov Report

Merging #67 into dev will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##                dev      #67   +/-   ##
=========================================
  Coverage     84.89%   84.89%           
  Complexity       96       96           
=========================================
  Files            16       16           
  Lines           331      331           
  Branches          1        1           
=========================================
  Hits            281      281           
  Misses           49       49           
  Partials          1        1

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[rosiel]

Since we're no longer using Travis, does this need to get updated to use github actions (or other replacement?)

[seth-shaw-unlv]

I think on the Tech Call the general feeling was that it was noisy and not very useful. Nobody was actually listening to the Slack #notifications channel.

[seth-shaw-unlv]

Won't use.