Cache bust bundle data to fix docker builds

Jamie had an issue running and building the new docker file that might affect other people.

I can't reproduce this myself and I didn't have this problem when upgrading ruby so I wonder if it's caused by earlier versions of bundler or binstubs in the shared folder.

Modern versions of bundler will install the bundler version specified in the gemfile automatically, 2.x was the version version to do this so maybe there were some teething issues that are now fixed.

```
api-1   | Activating bundler (~> 4.0) failed:
api-1   | Could not find 'bundler' (~> 4.0) - did find: [bundler-2.7.2,bundler-2.6.9]
api-1   | Checked in 'GEM_PATH=/root/.local/share/gem/ruby/3.4.0:/usr/local/lib/ruby/gems/3.4.0:/usr/local/bundle' , execute `gem env` for more information
api-1   |
api-1   | To install the version of bundler this project requires, run `gem install bundler -v '~> 4.0'`
```

Author: zetter-rpf

docker-compose.yml

@@ -26,7 +26,7 @@ services:
         condition: service_healthy
     volumes:
       - .:/app
-      - bundle-data:/usr/local/bundle
+      - bundle-data-v2:/usr/local/bundle
       - node_modules:/app/node_modules
       # This is here to avoid rails finding stale pid-files in tmp/pids and then
       # thinking it is already running:
@@ -55,5 +55,5 @@ services:
 
 volumes:
   postgres-data:
-  bundle-data:
+  bundle-data-v2:
   node_modules: