v3.0.0 - Gatsby v4 support

Fixes:

• Direct mutation of nodes not allowed #156

Note:

• Backwards compatible with Gatsby v3

BREAKING CHANGES:

• CloudinaryAsset nodes are not added for existing assets described by a content node
• When uploading remote images the relationship between parent and child node must be handled manually
• gatsbyImageData, fluid and fixed resolvers are only added to GraphQL Types configured using the transformTypes