Update NuGet file size limit to docs

doc/user/packages/nuget_repository/index.md

@@ -263,7 +263,7 @@ Prerequisite:
 
 When publishing packages:
 
-- The Package Registry on GitLab.com can store up to 500 MB of content.
+- The Package Registry on GitLab.com can store up to 5 GB of content.
   This limit is [configurable for self-managed GitLab instances](../../../administration/instance_limits.md#package-registry-limits).
 - If you publish the same package with the same version multiple times, each
   consecutive upload is saved as a separate file. When installing a package,