Remove Readonly modifier since DocumentNode is already readonly

src/cache/inmemory/documentTransformer.ts

@@ -18,7 +18,7 @@ export class DocumentTransformer {
     return this;
   }
 
-  public transform(document: Readonly<DocumentNode>): DocumentNode {
+  public transform(document: DocumentNode): DocumentNode {
     return this.transforms.reduce((document, transform) => {
       return transform(document);
     }, document);

src/cache/inmemory/types.ts

@@ -155,4 +155,4 @@ export interface ReadMergeModifyContext {
   varString?: string;
 }
 
-export type DocumentTransform = (document: Readonly<DocumentNode>) => DocumentNode
+export type DocumentTransform = (document: DocumentNode) => DocumentNode