Bump Rubygems version to v3.4 in CI

This will be needed to support Ruby 3.1 and 3.2.

.gitlab-ci.yml

@@ -131,7 +131,7 @@ workflow:
 
 variables:
   PG_VERSION: "12"
-  DEFAULT_CI_IMAGE: "${REGISTRY_HOST}/${REGISTRY_GROUP}/gitlab-build-images/debian-${DEBIAN_VERSION}-ruby-${RUBY_VERSION}.patched-golang-${GO_VERSION}-rust-${RUST_VERSION}-node-16.14-postgresql-${PG_VERSION}:rubygems-3.2-git-2.36-lfs-2.9-chrome-${CHROME_VERSION}-yarn-1.22-graphicsmagick-1.3.36"
+  DEFAULT_CI_IMAGE: "${REGISTRY_HOST}/${REGISTRY_GROUP}/gitlab-build-images/debian-${DEBIAN_VERSION}-ruby-${RUBY_VERSION}.patched-golang-${GO_VERSION}-rust-${RUST_VERSION}-node-16.14-postgresql-${PG_VERSION}:rubygems-${RUBYGEMS_VERSION}-git-2.36-lfs-2.9-chrome-${CHROME_VERSION}-yarn-1.22-graphicsmagick-1.3.36"
   # We set $GITLAB_DEPENDENCY_PROXY to another variable (since it's set at the group level and has higher precedence than .gitlab-ci.yml)
   # so that we can override $GITLAB_DEPENDENCY_PROXY_ADDRESS in workflow rules.
   GITLAB_DEPENDENCY_PROXY_ADDRESS: "${GITLAB_DEPENDENCY_PROXY}"
@@ -151,6 +151,7 @@ variables:
   CHROME_VERSION: "109"
   DOCKER_VERSION: "23.0.1"
   RUBY_VERSION: "2.7"
+  RUBYGEMS_VERSION: "3.4"
   GO_VERSION: "1.18"
   RUST_VERSION: "1.65"
 

.gitlab/ci/frontend.gitlab-ci.yml

@@ -3,7 +3,7 @@
     - .default-retry
     - .default-before_script
     - .assets-compile-cache
-  image: ${REGISTRY_HOST}/${REGISTRY_GROUP}/gitlab-build-images/debian-${DEBIAN_VERSION}-ruby-${RUBY_VERSION}-node-16.14:rubygems-3.2-git-2.33-lfs-2.9-yarn-1.22-graphicsmagick-1.3.36
+  image: ${REGISTRY_HOST}/${REGISTRY_GROUP}/gitlab-build-images/debian-${DEBIAN_VERSION}-ruby-${RUBY_VERSION}-node-16.14:rubygems-${RUBYGEMS_VERSION}-git-2.33-lfs-2.9-yarn-1.22-graphicsmagick-1.3.36
   variables:
     SETUP_DB: "false"
     WEBPACK_VENDOR_DLL: "true"