Bcon/make query optional monitor update (#192)

* make query optional

* updated query param as it is optional

* fix some linting errors

* better expression

* new linting problem

* updated version

* removed warn

* version bump

* updated default params and warn message

* oops put the warn in the wrong spot

lib/dogapi/v1/monitor.rb

@@ -16,10 +16,15 @@ def monitor(type, query, options = {})
         request(Net::HTTP::Post, "/api/#{API_VERSION}/monitor", nil, body, true)
       end
 
-      def update_monitor(monitor_id, query, options)
-        body = {
-          'query' => query,
-        }.merge options
+      def update_monitor(monitor_id, query = nil, options = {})
+        body = {}.merge options
+        unless query.nil?
+          body = {
+            'query' => query
+          }.merge body
+          warn '[DEPRECATION] query param is not required anymore and should be set to nil.'\
+             ' To update the query, set it in the options parameter instead'
+        end
 
         request(Net::HTTP::Put, "/api/#{API_VERSION}/monitor/#{monitor_id}", nil, body, true)
       end