Fix TraceResponse format to match spec (#243)

Author: agoallikmaa

src/TraceResponsePropagator.php

@@ -17,8 +17,8 @@
  */
 final class TraceResponsePropagator implements ResponsePropagator
 {
-    const IS_SAMPLED = '1';
-    const NOT_SAMPLED = '0';
+    const IS_SAMPLED = '01';
+    const NOT_SAMPLED = '00';
     const SUPPORTED_VERSION = '00';
     const TRACERESPONSE = 'traceresponse';
 

tests/Unit/PropagatorTest.php

@@ -19,8 +19,8 @@ class PropagatorTest extends TestCase
 {
     private const TRACE_ID = '5759e988bd862e3fe1be46a994272793';
     private const SPAN_ID = '53995c3f42cd8ad8';
-    private const TRACERESPONSE_HEADER_SAMPLED = '00-5759e988bd862e3fe1be46a994272793-53995c3f42cd8ad8-1';
-    private const TRACERESPONSE_HEADER_NOT_SAMPLED = '00-5759e988bd862e3fe1be46a994272793-53995c3f42cd8ad8-0';
+    private const TRACERESPONSE_HEADER_SAMPLED = '00-5759e988bd862e3fe1be46a994272793-53995c3f42cd8ad8-01';
+    private const TRACERESPONSE_HEADER_NOT_SAMPLED = '00-5759e988bd862e3fe1be46a994272793-53995c3f42cd8ad8-00';
 
     /**
      * @test