Fix DevContainer post-create warnings (#23977)

.devcontainer/post-create.sh

@@ -3,14 +3,16 @@
 set -e # Fail the whole script on first error
 
 # Fetch Ruby gem dependencies
-bundle install --path vendor/bundle --with='development test'
-
-# Fetch Javascript dependencies
-yarn install
+bundle config path 'vendor/bundle'
+bundle config with 'development test'
+bundle install
 
 # Make Gemfile.lock pristine again
 git checkout -- Gemfile.lock
 
+# Fetch Javascript dependencies
+yarn --frozen-lockfile
+
 # [re]create, migrate, and seed the test database
 RAILS_ENV=test ./bin/rails db:setup