chore: upgrade slack ruby gem to v2.2.0

Gemfile

@@ -92,7 +92,7 @@ gem 'twitty', '~> 0.1.5'
 # facebook client
 gem 'koala'
 # slack client
-gem 'slack-ruby-client', '~> 2.0.0'
+gem 'slack-ruby-client', '~> 2.2.0'
 # for dialogflow integrations
 gem 'google-cloud-dialogflow-v2'
 gem 'grpc'

Gemfile.lock

@@ -273,7 +273,7 @@ GEM
       googleauth (~> 1.0)
       grpc (~> 1.36)
     geocoder (1.8.1)
-    gli (2.21.0)
+    gli (2.21.1)
     globalid (1.2.1)
       activesupport (>= 6.1)
     gmail_xoauth (0.4.2)
@@ -732,13 +732,12 @@ GEM
       json (>= 1.8, < 3)
       simplecov-html (~> 0.10.0)
     simplecov-html (0.10.2)
-    slack-ruby-client (2.0.0)
+    slack-ruby-client (2.2.0)
       faraday (>= 2.0)
       faraday-mashify
       faraday-multipart
       gli
       hashie
-      websocket-driver
     snaky_hash (2.0.1)
       hashie
       version_gem (~> 1.1, >= 1.1.1)
@@ -935,7 +934,7 @@ DEPENDENCIES
   sidekiq (>= 7.1.3)
   sidekiq-cron (>= 1.10.1)
   simplecov (= 0.17.1)
-  slack-ruby-client (~> 2.0.0)
+  slack-ruby-client (~> 2.2.0)
   spring
   spring-watcher-listen
   squasher