Maintenance: Bump slack-ruby-client from 0.17.0 to 1.0.0

Bumps [slack-ruby-client](https://github.com/slack-ruby/slack-ruby-client) from 0.17.0 to 1.0.0.
- [Release notes](https://github.com/slack-ruby/slack-ruby-client/releases)
- [Changelog](https://github.com/slack-ruby/slack-ruby-client/blob/master/CHANGELOG.md)
- [Commits](https://github.com/slack-ruby/slack-ruby-client/compare/v0.17.0...v1.0.0)

Gemfile.lock

@@ -227,7 +227,7 @@ GEM
     faraday-net_http_persistent (1.2.0)
     faraday-patron (1.0.0)
     faraday-rack (1.0.0)
-    faraday_middleware (1.1.0)
+    faraday_middleware (1.2.0)
       faraday (~> 1.0)
     ffi (1.15.4)
     ffi-compiler (1.0.1)
@@ -567,7 +567,7 @@ GEM
       simplecov (>= 0.4.1)
     simplecov_json_formatter (0.1.3)
     slack-notifier (2.4.0)
-    slack-ruby-client (0.17.0)
+    slack-ruby-client (1.0.0)
       faraday (>= 1.0)
       faraday_middleware
       gli