Don't send empty Slack messages

lib/version_checker.rb

@@ -27,7 +27,7 @@ def print_version_discrepancies
       puts "team: #{team}\n#{message}"
 
       poster = Slack::Poster.new(ENV["SLACK_WEBHOOK"], slack_options(team))
-      poster.send_message(message.to_s) unless message.nil?
+      poster.send_message(message.to_s) unless message.empty?
     end
   end
 

spec/version_checker_spec.rb

@@ -19,7 +19,6 @@
   end
 
   it "detects when there are no files changed since the last release that are built into the gem" do
-    stub_slack_poster_call_with_no_changes
     stub_devdocs_call
     stub_rubygems_call("1.2.3")
     stub_files_changed_since_tag(["README.md"])
@@ -65,18 +64,4 @@ def stub_slack_poster_call_with_changes
     )
     .to_return(status: 200)
   end
-
-  def stub_slack_poster_call_with_no_changes
-    stub_request(:post, "https://slack/webhook")
-         .with(
-           body: { "payload" => "{\"icon_emoji\":\":gem:\",\"username\":\"Gem Release Bot\",\"channel\":\"#platform-security-reliability-team\",\"text\":\"\"}" },
-           headers: {
-             "Accept" => "*/*",
-             "Accept-Encoding" => "gzip;q=1.0,deflate;q=0.6,identity;q=0.3",
-             "Content-Type" => "application/x-www-form-urlencoded",
-             "User-Agent" => "Faraday v2.7.11",
-           },
-         )
-         .to_return(status: 200, body: "", headers: {})
-  end
 end