Add Racket 9.2 Docker image to DockerHub

[byteshiva]

Please add the Racket 9.2 Docker image to racket/racket on DockerHub.

Requested tags:

· racket:9.2
· racket:9.2-full
· Update racket:latest to 9.2

Release notes: https://blog.racket-lang.org/2026/05/racket-v9-2.html