Fix gtfs tracker deployment (#683)

* Fix Features Tracker deployment

Update file names

* Update mkdocs.yml

* Rename Google.png to google.png

Author: etienne0101

config/en/mkdocs.yml

@@ -41,11 +41,11 @@ theme:
   icon:
     repo: fontawesome/brands/github
 extra_css:
-  - assets/stylesheets/gtfs_tracker.css
+  - assets/stylesheets/gtfs-tracker.css
   - assets/stylesheets/extra.css
   - assets/stylesheets/footer.css
 extra_javascript:
-  - assets/javascript/gtfs_tracker.js
+  - assets/javascript/gtfs-tracker.js
   - assets/javascript/anchor-redirects.js
   - assets/javascript/languageSwitchUrls.js
 extra: