Fix error in specs with Rails 8.0

-:results => [{:message => "", :name => "Database", :status => "OK"}, {:message => "different values (now: 1990-01-01 00:00:00 +0000, fetched: false)", :name => "Redis", :status => "ERROR"}],
+:results => [{:message => "", :name => "Database", :status => "OK"}, {:message => "different values (now: Mon, 01 Jan 1990 00:00:00 +0000, fetched: false)", :name => "Redis", :status => "ERROR"}],

Rails 7.2 => Time.now.to_formatted_s(:rfc2822) => 1990-01-01 00:00:00 +0100
Rails 8.0 => Time.now.to_formatted_s(:rfc2822) => Mon, 01 Jan 1990 00:00:00 +0100

Rails 7.2 => Time.now => 1990-01-01 00:00:00 +0100
Rails 8.0 => Time.now => 1990-01-01 00:00:00 +0100

lib/health_monitor/providers/redis.rb

@@ -52,12 +52,12 @@ def redis_connection
       end
 
       def check_values!
-        time = Time.now.to_formatted_s(:rfc2822)
+        time = Time.now
 
         @redis.set(@key, time)
         fetched = @redis.get(@key)
 
-        raise "different values (now: #{time}, fetched: #{fetched})" if fetched != time
+        raise "different values (now: #{time}, fetched: #{fetched})" if fetched != time.to_s
       end
 
       def check_max_used_memory!