[feature request] json path support wildcard

### Expected behavior
add build arg `REPO_FROM` to all artifact

like

```yaml
patches:
- op: add
path: /build/artifacts[*]/docker/buildArgs
value:
REPO_FROM: 'registry.demo.com/avatar/internal/'
```

### Actual behavior
error

applying profiles: applying profile "development": invalid path: /build/artifacts[*]/docker/buildArgs

### Information

- Skaffold version: version... 5df17d6,
- Operating system: ... macOS 10.14.6
- Contents of skaffold.yaml:

```yaml
apiVersion: skaffold/v2beta4
kind: Config
metadata:
name: erp
build:
local:
push: true
useBuildkit: true
artifacts:
- image: registry.demo.com/avatar/mpaas/shipconsole
context: ../
docker:
dockerfile: avatar/auto/ship/web.Dockerfile
- image: registry.demo.com/avatar/mpaas/shipmobile
context: ../
docker:
dockerfile: avatar/auto/ship/mobile.Dockerfile
- image: registry.demo.com/avatar/mpaas/shipbackground
context: ../
docker:
dockerfile: avatar/auto/ship/background.Dockerfile

profiles:
- name: development
build:
tagPolicy:
dateTime:
format: "dev2006-01-02_15-04-05.999_MST"
timezone: "Local"
patches:
- op: add
path: /build/artifacts[*]/docker/buildArgs
value:
REPO_FROM: 'registry.demo.com/avatar/internal/'

- name: nocache
patches:
- op: add
path: /build/artifacts/0/docker/noCache
value: true

```

### Steps to reproduce the behavior
```bash
skaffold build -p development --build-image=ship
```