Expose method to set icon and cover

Author: KoditkarVedant

Src/Notion.Client/Api/Pages/RequestParams/PagesCreateParameters/PagesCreateParametersBuilder.cs

@@ -34,6 +34,18 @@ public PagesCreateParametersBuilder AddPageContent(Block block)
             return this;
         }
 
+        public PagesCreateParametersBuilder SetIcon(IPageIcon pageIcon)
+        {
+            icon = pageIcon;
+            return this;
+        }
+
+        public PagesCreateParametersBuilder SetCover(FileObject pageCover)
+        {
+            cover = pageCover;
+            return this;
+        }
+
         public PagesCreateParameters Build()
         {
             return new PagesCreateParameters