Update Netlify CMS - Githubissues

We should remove our custom CMS build and update to the latest release as soon as the following PRs are merged:

[x] https://github.com/netlify/netlify-cms/pull/719 - fix relation widget so that it doesn't require a page reload to preview them correctly
[x] https://github.com/netlify/netlify-cms/pull/994 - fix thumbnails of new images not appearing immediately if uploaded to a private repo
[x] https://github.com/netlify/netlify-cms/pull/998 - fix for the latest Netlify CMS master which shows a proptype warning on the console
[x] ~Verify if new content creation obeys slug configuration (https://github.com/marzeelabs/uhub/issues/69)~
[x] https://github.com/netlify/netlify-cms/pull/1199 - fix regression in list relation previews

marzeelabs / besugo