gatsby-theme-contentful-blog: adding blog support as per shows error

[ischyron]

9:54:47 AM: info [gatsby-theme-abstract-blog] creating pages
9:54:47 AM: error "gatsby-theme-abstract-blog" threw an error while running the createPages lifecycle:
9:54:47 AM: Interface field Image.gatsbyImageData expects type GatsbyImageData but ContentfulAsset.gatsbyImageData is type JSON.
9:54:47 AM:   140 |       }
9:54:47 AM:   141 |
9:54:47 AM: > 142 |   const result = await graphql(`
      |                        ^
  143 |     {
  144 |       posts: allBlogPost {
  145 |         nodes {
9:54:47 AM: 
9:54:47 AM:   Error: Interface field Image.gatsbyImageData expects type GatsbyImageData but   ContentfulAsset.gatsbyImageData is type JSON.
9:54:47 AM: