Cloudinary "multiple" doesn't return array if only one image is selected

Describe the bug When selecting 2 images via Cloudinary media_library, the image strings are saved in markdown as an array. When selecting 1 image, it is saved in markdown as a string. This causes the following error during build:

warn There are conflicting field types in your data.

If you have explicitly defined a type for those fields, you can safely ignore this warning message.
Otherwise, Gatsby will omit those fields from the GraphQL schema.

If you know all field types in advance, the best strategy is to explicitly define them with the `createTypes` action, and skip inference with the `@dontInfer` directive.
See https://www.gatsbyjs.org/docs/actions/#createTypes
MarkdownRemark.frontmatter.images:
 - type: [string]
   value: [ 'https://res.cloudinary.com/testgatsbycloudinarymultiple/image/upload/v1566436788/samples/cloudinary-group.jpg', ... ]
   source: File "src/pages/blog/2019-08-21-multiple-via-cloudinary.md"
 - type: string
   value: 'https://res.cloudinary.com/testgatsbycloudinarymultiple/image/upload/v1566436775/sample.jpg'
   source: File "src/pages/blog/2019-08-21-single-via-cloudinary.md"
success building schema - 0.432 s
success createPages - 0.086 s
success createPagesStatefully - 0.074 s
success onPreExtractQueries - 0.032 s
success update schema - 0.075 s

 ERROR #85907  GRAPHQL

There was an error in your GraphQL query:

- Unknown field 'images' on type 'MarkdownRemarkFrontmatter'.

To Reproduce

1. Create a post with multiple images via Cloudinary media_library
2. Create a post with 1 image via Cloudinary media_library
3. The build now fails because the second post is a string, not an array

Expected behavior When configured for multiple: true, it should always return an array even if only one image is selected.

Applicable Versions:

"gatsby": "^2.13.31",
"gatsby-image": "^2.0.23",
"gatsby-plugin-netlify": "^2.0.6",
"gatsby-plugin-netlify-cms": "^4.1.6",
"netlify-cms-app": "^2.9.6",
"netlify-cms-media-library-cloudinary": "^1.3.2"

CMS configuration

backend:
  name: git-gateway
  branch: master

public_folder: /img

media_library:
  name: cloudinary
  config:
    cloud_name: testgatsbycloudinarymultiple
    api_key: 358577637849857
    multiple: true

collections:
  - name: "blog"
    label: "Blog"
    folder: "src/pages/blog"
    create: true
    slug: "{{year}}-{{month}}-{{day}}-{{slug}}"
    fields:
      - {
          label: "Template Key",
          name: "templateKey",
          widget: "hidden",
          default: "blog-post",
        }
      - { label: "Title", name: "title", widget: "string" }
      - { label: "Publish Date", name: "date", widget: "datetime" }
      - { label: "Description", name: "description", widget: "text" }
      - { label: "Featured Post", name: "featuredpost", widget: "boolean" }
      - { label: "Images", name: "images", widget: image }
      - { label: "Body", name: "body", widget: "markdown" }
      - { label: "Tags", name: "tags", widget: "list" }

Markdown Examples Multiple Images:

---
templateKey: blog-post
title: Multiple Via Cloudinary
date: 2019-08-22T01:49:09.250Z
description: test
featuredpost: false
images:
  - >-
    https://res.cloudinary.com/testgatsbycloudinarymultiple/image/upload/v1566436788/samples/cloudinary-group.jpg
  - >-
    https://res.cloudinary.com/testgatsbycloudinarymultiple/image/upload/v1566436787/samples/imagecon-group.jpg
tags:
  - test
---

Test

Single Image:

---
templateKey: blog-post
title: Single Via Cloudinary
date: 2019-08-22T02:07:23.914Z
description: test
featuredpost: false
images: >-
  https://res.cloudinary.com/testgatsbycloudinarymultiple/image/upload/v1566436775/sample.jpg
tags:
  - test
---
Test

Additional context I created a test repo and published in case that helps: Test Repository: https://github.com/zacharysierakowski/gatsby-cloudinary-multiple-test Test URL: https://gatsby-cloudinary-multiple-test.netlify.com/admin/

[erquhart]

No just haven’t published yet, I’ll get one out today - note that this will be in beta for a bit, so it will initially only be available via netlify-cms@beta or netlify-cms-app@beta.

[zacharysierakowski]

@erquhart, this was an easier change than I expected. I created a PR here. If you have some time to check it out, it’d be appreciated. Thanks again!