Revert "[gitlab] simplify gql schema download"

This reverts commit 40ced41cce.

GitLab removed the SDL files from the docs: baedeb4ee8

scripts/download-gql-schema.ts

@@ -29,11 +29,7 @@ const schemas: [
   [string | URL, GotOptions & { isStream?: true | undefined }],
 ][] = [
   ['github', 'graphql', ['https://docs.github.com/public/schema.docs.graphql', {}]],
-  [
-    'gitlab',
-    'graphql',
-    ['https://docs.gitlab.com/ee/api/graphql/reference/gitlab_schema.graphql', {}],
-  ],
+  ['gitlab', 'json', ['https://gitlab.com/api/graphql', introspection]],
 ];
 
 Promise.all(

src/vendor/gitlab/codegen.toml

@@ -1,5 +1,5 @@
 overwrite = true
-schema= 'src/vendor/gitlab/schema.graphql'
+schema= 'src/vendor/gitlab/schema.json'
 
 [config]
   typesPrefix = 'GL'