Make sure upgrade docs for each released version have the correct supported upgrade path listed.

According to the upgrade section of the release docs in the Harbor repo, https://github.com/goharbor/harbor/blob/main/RELEASES.md#upgrade-path-and-support-policy

>The upgrade path for Harbor is (1) 2.2.x patch releases are always compatible with its major and minor version. For example, previous released 2.2.x can be upgraded to most recent 2.2.3 release. (2) Harbor only supports two previous minor releases to upgrade to current minor release. For example, 2.3.0 will only support 2.1.0 and 2.2.0 to upgrade from, 2.0.0 to 2.3.0 is not supported. One should upgrade to 2.2.0 first, then to 2.3.0. The Harbor project maintains release branches for the three most recent minor releases, each minor release will be maintained for approximately 9 months.

We should make sure the each of the following pages lists the correct versions of the supported upgrade path, and links to previous upgrade pages.

* https://goharbor.io/docs/2.4.0/administration/upgrade/
* https://goharbor.io/docs/2.3.0/administration/upgrade/
* https://goharbor.io/docs/2.2.0/administration/upgrade/
* https://goharbor.io/docs/2.1.0/administration/upgrade/
* https://goharbor.io/docs/2.0.0/administration/upgrade/
* https://goharbor.io/docs/1.10/administration/upgrade/