chore: uses span error API.

Author: jcchavezs

src/Zipkin/Instrumentation/Http/Server/DefaultParser.php

@@ -31,9 +31,4 @@ public function response(ResponseInterface $response, TraceContext $context, Spa
             $span->tag(Tags\ERROR, (string) $response->getStatusCode());
         }
     }
-
-    public function error(Throwable $e, TraceContext $context, SpanCustomizer $span): void
-    {
-        $span->tag(Tags\ERROR, $e->getMessage());
-    }
 }

src/Zipkin/Instrumentation/Http/Server/Middleware.php

@@ -80,7 +80,7 @@ public function process(ServerRequestInterface $request, RequestHandlerInterface
             $this->parser->response($response, $span->getContext(), $spanCustomizer);
             return $response;
         } catch (Throwable $e) {
-            $this->parser->error($e, $span->getContext(), $spanCustomizer);
+            $span->setError($e);
             throw $e;
         } finally {
             $span->finish();

src/Zipkin/Instrumentation/Http/Server/Parser.php

@@ -43,11 +43,4 @@ public function request(ServerRequestInterface $request, TraceContext $context,
      * payload can be added.
      */
     public function response(ResponseInterface $response, TraceContext $context, SpanCustomizer $span): void;
-
-    /**
-     * error parses the exception when doing a HTTP call, usually it is good enough to tag
-     * the throwable message but depending on the wrapping client, one might want to enrich
-     * the error with meaningful information from the exception.
-     */
-    public function error(Throwable $e, TraceContext $context, SpanCustomizer $span): void;
 }