Default to stable Ruby 3.1 release (#1317)

Author: olivierlacan

containers/ruby-rails-postgres/.devcontainer/Dockerfile

@@ -1,5 +1,5 @@
 # [Choice] Ruby version (use -bullseye variants on local arm64/Apple Silicon): 3, 3.1, 3.0, 2, 2.7, 2.6, 3-bullseye, 3.1-bullseye, 3.0-bullseye, 2-bullseye, 2.7-bullseye, 2.6-bullseye, 3-buster, 3.1-buster, 3.0-buster, 2-buster, 2.7-buster, 2.6-buster
-ARG VARIANT=2-bullseye
+ARG VARIANT=3.1-bullseye
 FROM mcr.microsoft.com/vscode/devcontainers/ruby:${VARIANT}
 
 # Install Rails

containers/ruby-rails-postgres/.devcontainer/docker-compose.yml

@@ -9,7 +9,7 @@ services:
         # Update 'VARIANT' to pick a version of Ruby: 3, 3.1, 3.0, 2, 2.7, 2.6
         # Append -bullseye or -buster to pin to an OS version.
         # Use -bullseye variants on local arm64/Apple Silicon.
-        VARIANT: "2-bullseye"
+        VARIANT: "3.1-bullseye"
         # Optional Node.js version to install
         NODE_VERSION: "lts/*"