Helm diff should flatten ConfigMapList objects

[madaraszg-tulip]

This issue is similar to #201.
There are multiple types of list objects, one of them is ConfigMapList which stores a number of ConfigMap entries.
It would be great if helm diff expanded these too.

The errors I'm getting are:
Error: Found duplicate key "namespace, , ConfigMapList (v1)" in manifest

[yxxhero]

@madaraszg-tulip could you give me some example? So I can debug and fix it.

[madaraszg-tulip]

helm-diff-test.zip

Install this chart, then change templates/configmaplist2.yaml and try helm diff

[yxxhero]

@mumoshu ping. WDYT?

[yxxhero]

@madaraszg-tulip fixed. thanks your advice. I match all list resource.

[yxxhero]

see: https://github.com/databus23/helm-diff/releases/tag/v3.9.6 released.