Gogs: Fix data persistence

Gogs stores all git repositories in /data/git/gogs-repositories,
so they are lost after each restart. This results in error 500 when
you try to open the repository.

Also you can find generated SSH keys in /data/ssh that are being lost too.

This commit changes the gogs-data volume to point to /data to achieve
data persistence and to avoid creation of dangling volumes.

templates/gogs/0/docker-compose.yml.tpl

@@ -3,7 +3,7 @@ services:
   gogs:
     image: gogs/gogs:0.11.19
     volumes:
-      - gogs-data:/data/gogs
+      - gogs-data:/data
 {{- if ne .Values.db_link ""}}
     external_links:
       - ${db_link}:db