chore: update gatsby to v3 (#5057)

website/content/blog/implementing-a-jekyll-cms-in-3-days.md

@@ -6,7 +6,7 @@ description: >-
   website. Using Netlify CMS they added content management to a Jekyll site in
   three days.
 twitter_image: /img/netlify-cms.png
-date: '2019-06-06'
+date: 2019-06-06T12:00:00.000Z
 canonical_url: https://www.dwolla.com/updates/implementing-netlify-cms/
 ---
 
@@ -61,7 +61,7 @@ If you were using the built-in Jekyll gems and build process that GitHub provide
 <figure>
   <figcaption>Gemfile</figcaption>
 
-  ```x
+  ```bash
   source "https://rubygems.org"
   gem 'github-pages'
   ```
@@ -70,7 +70,7 @@ If you were using the built-in Jekyll gems and build process that GitHub provide
 <figure>
   <figcaption>netlify.toml</figcaption>
 
-  ```x
+  ```bash
   [build]
   publish = "_site/"
   command = "jekyll build"
@@ -83,7 +83,7 @@ Once you’re satisfied that everything looks good and is deploying correctly fr
 
 Netlify CMS itself consists of a [Single Page Application](https://en.wikipedia.org/wiki/Single-page_application) built with [React](https://reactjs.org/) that lives in an admin folder on your site. For Jekyll, it goes right at the root of your project. It will contain two files:
 
-```x
+```bash
 admin
  ├ index.html
  └ config.yml

website/content/blog/netlify-cms-2-0-launches-with-bitbucket-support-and-a-new-monorepo-architecture.md

@@ -7,7 +7,7 @@ description: >-
   Announcing the release of Netlify CMS v2.0, with new Bitbucket support and an
   improved project architecture designed to ease contribution and the extension
   of features.
-date: '2018-07-26'
+date: 2018-07-26T12:00:00.000Z
 ---
 Today we’re releasing Netlify CMS 2.0, which adds support for using Bitbucket as a backend. 
 

website/content/blog/netlify-cms-now-supports-gitlab-as-a-backend.md

@@ -5,7 +5,7 @@ description: >-
   Netlify CMS, the open source, headless CMS that provides a user-friendly UI
   around your Git repository, can now be used with GitLab in addition to
   GitHub.
-date: '2018-06-13'
+date: 2018-06-13T00:00:10.000Z
 ---
 Netlify CMS is releasing support for GitLab as a backend, creating the world's first completely open source stack for Git-based content editing.