Fixes broken link in metadata.json

Author: hlfernandez

metadata/metadata.json

@@ -5663,7 +5663,7 @@
        "'config.json' to the actual name the JSON specification file"
     ],
     "test_invocation_specific": "generate_dockerfile.sh config.json",
-    "test_data_url": "http://evolution6.i3s.up.pt/static/pegi3s/dockerfiles/r_builder/config.json",
+    "test_data_url": "http://evolution6.i3s.up.pt/static/pegi3s/dockerfiles/input_test_data/r_builder/config.json",
     "test_results_url": "http://evolution6.i3s.up.pt/static/pegi3s/dockerfiles/output_test_data/r_builder_output.zip",
     "icon": "",
     "input_data_type": ["json"],