Automated documentation update (#263)

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

src/r-apt/README.md

@@ -35,9 +35,7 @@ Installs the latest R, some R packages, and needed dependencies. Note: May requi
 
 ## Supported platforms
 
-`linux/amd64` platform `debian`, `ubuntu:focal` and `ubuntu:jammy`.
-
-If the `useTesting` is `true`, `linux/arm64` platform `debian` also supported.
+`linux/amd64` and `linux/arm64` platforms `debian`, `ubuntu` LTS.
 
 Note that this Feature only supports non-R images. If R is already installed, installation will be failed.