Added support for GraphQL mutations!

Through mutations, you are now able to modify data through your GraphQL queries:

mutation {
  updatePost(id: 5, title: "New title") {
    title
  }
}

The following mutation fields have been added to the schema:

• createPost
• updatePost
• setFeaturedImageforCustomPost
• removeFeaturedImageforCustomPost
• addCommentToCustomPost
• replyComment
• loginUser
• logoutUser

Nested mutations is the ability to perform mutations on a type other than the root type in GraphQL.

For instance, the mutation query from above can also be executed through this nested mutation, on type Post:

mutation {
  post(id: 5) {
    update(title: "New title") {
      title
    }
  }
}

Mutations can also modify data on the result from another mutation:

mutation {
  createPost(title: "First title") {
    id
    update(title: "Second title", contentAs: { html: "Some content" } ) {
      title
      content
      addComment(commentAs: { html: "My first comment" }) {
        id
        content
        date
      }
    }
  }
}

Nested mutations have been requested for the GraphQL spec but not yet approved, hence Gato GraphQL adds support for them as an opt-in feature, via module "Nested Mutations" (which must be enabled).

Nested mutations change the root type, from QueryRoot and MutationRoot, to a single Root type handling both queries and mutations:

In addition, a "Mutation Scheme" section has been added to a Schema Configuration, allowing to enable/disable nested mutations for a specific Custom Endpoint or Persisted Query.

The following nested mutation fields have been added to the schema:

• CustomPost.update
• CustomPost.setFeaturedImage
• CustomPost.removeFeaturedImage
• CustomPost.addComment
• Comment.reply

Starting from this version, the plugin runs without any issue in PHP 8.1.