Use yaml lists:
```yaml
ignore:
- generated
- "*.template.yaml"
```
instead of multiline strings:
```yaml
ignore: |
generated
*.template.yaml
```
This also fixes the wrong error messages when using the new config
format with ymallit v1.8.0/v1.8.1.
The only problem I see is that this will break config files with the
latter ignore pattern format.