offload: version update (#24680)

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## Description

Updated min version supported by Offload to 4.68 for nudge
functionality.

## Related issues or tickets


https://docker.slack.com/archives/C09ARNANZCJ/p1775759784277949?thread_ts=1775557490.573449&cid=C09ARNANZCJ

## Reviews

<!-- Notes for reviewers here -->
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- [ ] Technical review

---------

Signed-off-by: Craig Osterhout <craig.osterhout@docker.com>

Author: craig-osterhout

content/manuals/offload/troubleshoot.md

@@ -15,7 +15,7 @@ Docker Offload requires:
 - An active internet connection
 - No restrictive proxy or firewall blocking traffic to Docker Cloud
 - Access to Docker Offload
-- Docker Desktop 4.65 or later
+- Docker Desktop 4.68 or later
 
 Docker Desktop uses Offload to run both builds and containers in the cloud.
 If builds or containers are failing to run, falling back to local, or reporting

data/summary.yaml

@@ -153,7 +153,7 @@ Docker CLI OpenTelemetry:
   requires: Docker Engine [26.1.0](/manuals/engine/release-notes/26.1.md#2610) and later
 Docker Offload:
   subscription: [Docker Offload]
-  requires: Docker Desktop 4.65 and later
+  requires: Docker Desktop 4.68 or later
 docker compose alpha:
   availability: Experimental
 Docker Debug: