fix: upgrade core dependency (#10)

contributors: @MollocH

Author: cawolf

composer.json

@@ -19,7 +19,7 @@
   "require": {
     "php": "^7.1.33",
     "ext-json": "*",
-    "auxmoney/opentracing-bundle-core": "^0.5",
+    "auxmoney/opentracing-bundle-core": "^0.6",
     "opentracing/opentracing": "1.0.0-beta5@beta",
     "jcchavezs/zipkin-opentracing": "^0.1"
   },