adjust elastic mapping link

Author: mlodic

docs/IntelOwl/advanced_configuration.md

@@ -49,7 +49,7 @@ To activate this feature, it is necessary to set `ELASTICSEARCH_BI_ENABLED` to `
 `ELASTICSEARCH_BI_HOST` to `elasticsearch:9200`
 or your elasticsearch server.
 
-An [index template](https://github.com/intelowlproject/IntelOwl/configuration/elastic_search_mappings/intel_owl_bi.json) is created after the first bulk submission of reports.
+An [index template](https://github.com/intelowlproject/IntelOwl/blob/master/configuration/elastic_search_mappings/intel_owl_bi.json) is created after the first bulk submission of reports.
 If you want to use kibana to visualize your data/make dashboard, you must create an index pattern:
 Go to Kibana -> Discover -> Stack Management -> Index Patterns -> search for your index and use as time field `timestamp`