Add support for patchesJson6902

[tblaisot]

Expected behavior

Adding patchesJson6902 field in the main kustomisation.yaml file should work as in kustomize when using ship update

Actual behavior

Ship update delete all added field in kustomization.yaml

Information

• Ship version: 0.49.0
• helm: 2.14.1
• kustomize: 2.0.3
• terraform: 0.11.14
• Docker version: 18.09.7
• Command line run: ship update

Steps to reproduce the behavior

1. do a ship init git::https://gitlab.com/charts/gitlab/
2. create any patch
3. create a file my-patch.json containing:

[{"op":"remove","path":"/metadata/labels/release"}]

3. edit the root kustomization.yaml to add

patchesJson6902:
  - target:
      kind: Deployment
      namespace: default
      name: gitlab-unicorn
    path: my-patch.json

4. do a ship update
5. open root kustomization.yaml => the added code has disappeared

Even if the UI doesn't support such avanced kustomization it will be nice if it doesn't delete all or if there was a way to add patches because kustomize patchesStrategicMerge doesn't allow deletion of resources

[laverya]

This makes sense, and shouldn't be too much work to persist - though I don't think we'll be adding a UI for json patches soon