fix: change zipkin annotations timestamp from string to int (#1944)

Co-authored-by: Kayla Reopelle <[email protected]>

Author: chipiga

exporter/zipkin/lib/opentelemetry/exporter/zipkin/transformer.rb

@@ -117,12 +117,12 @@ def add_annotations(zipkin_span, span_data)
           events = span_data.events.map do |event|
             if event.attributes.keys.length.zero?
               {
-                timestamp: (event.timestamp / 1_000).to_s,
+                timestamp: event.timestamp / 1_000,
                 value: event.name
               }
             else
               {
-                timestamp: (event.timestamp / 1_000).to_s,
+                timestamp: event.timestamp / 1_000,
                 value: { event.name => event.attributes.transform_values(&:to_s) }.to_json
               }
             end

exporter/zipkin/test/opentelemetry/exporters/zipkin/transformer_test.rb

@@ -55,10 +55,10 @@
     annotation_one = encoded_span[:annotations].first
     annotation_two = encoded_span[:annotations][1]
 
-    _(annotation_one[:timestamp]).must_equal((events[0].timestamp / 1_000).to_s)
+    _(annotation_one[:timestamp]).must_equal(events[0].timestamp / 1_000)
     _(annotation_one[:value]).must_equal({ 'event_with_attribs' => { 'ekey' => 'evalue' } }.to_json)
 
-    _(annotation_two[:timestamp]).must_equal((events[1].timestamp / 1_000).to_s)
+    _(annotation_two[:timestamp]).must_equal(events[1].timestamp / 1_000)
     _(annotation_two[:value]).must_equal('event_no_attrib')
 
     tags = encoded_span['tags']
@@ -115,7 +115,7 @@
 
     annotation_one = encoded_span[:annotations].first
 
-    _(annotation_one[:timestamp]).must_equal((events[0].timestamp / 1000).to_s)
+    _(annotation_one[:timestamp]).must_equal(events[0].timestamp / 1000)
     _(annotation_one[:value]).must_equal({ 'event_with_attribs' => { 'ekey' => '["evalue"]' } }.to_json)
 
     tags = encoded_span['tags']