Add combined GraphQL update rake task

doc/development/rake_tasks.md

@@ -340,3 +340,7 @@ bundle exec rake gitlab:graphql:schema:dump
 ```
 
 This uses GraphQL Ruby's built-in Rake tasks to generate files in both [IDL](https://www.prisma.io/blog/graphql-sdl-schema-definition-language-6755bcb9ce51) and JSON formats.
+
+### Update documentation and schema definitions
+
+The following command combines the intent of [Update GraphQL documentation and schema definitions](#update-graphql-documentation-and-schema-definitions) and [Update machine-readable schema files](#update-machine-readable-schema-files):

lib/tasks/gitlab/graphql.rake

@@ -130,6 +130,9 @@ namespace :gitlab do
         abort
       end
     end
+
+    desc 'GitLab | GraphQL | Update GraphQL docs and schema'
+    task update_all: [:compile_docs, 'schema:dump']
   end
 end