Fix varnish docker-compose yaml links

docker-compose-services/varnish/README.md

@@ -3,13 +3,13 @@
 This recipe allows you to configure a Varnish reverse proxy for your project.
 
 The Varnish service inserts itself between ddev-router and the web container, so that calls
-to the web container are routed through Varnish first. The [docker-compose.varnish.yaml](docker-compose.varnish.yaml)
+to the web container are routed through Varnish first. The [docker-compose.varnish.yaml](https://github.com/drud/ddev-contrib/blob/master/docker-compose-services/varnish/docker-compose.varnish.yml)
 replaces the ```VIRTUAL_HOST``` variable of the web container with a subdomain of
 the website URL (see below) and uses the default domain as its own host name.
 
 To enable Varnish in your project follow these steps:
 
-1. Copy [docker-compose.varnish.yaml](docker-compose.varnish.yaml) into your project's .ddev directory.
+1. Copy [docker-compose.varnish.yaml](https://github.com/drud/ddev-contrib/blob/master/docker-compose-services/varnish/docker-compose.varnish.yml) into your project's .ddev directory.
 2. Create a directory named _varnish_ in your project's .ddev directory.
 3. Copy the [default.vcl](default.vcl) in this directoy.
 4. Run `ddev start`.