Fix broken docker-compose example
Fix broken docker-compose example

Using latest docker-compose distributed with manjaro I got the following error:

```
[mop@gustav-theodor kalkspace-mete]$ docker-compose up -d
ERROR: Version in "./docker-compose.yml" is invalid - it should be a string.
```

Fix seems easy enough :D
YtvwlD/mete,chaosdorf/mete,chaosdorf/mete,chaosdorf/mete,chaosdorf/mete,YtvwlD/mete,YtvwlD/mete,YtvwlD/mete