Use ruby:2.7 instead of alpine

There is a problem installing gem
when using ruby:2.7-alpine on shared runner:

https://gitlab.com/gitlab-org/gitlab/-/issues/335641#note_622171906

.gitlab/ci/review.gitlab-ci.yml

@@ -25,7 +25,7 @@ review-build-cng:
   extends:
     - .default-retry
     - .review:rules:review-build-cng
-  image: ${GITLAB_DEPENDENCY_PROXY}ruby:2.7-alpine
+  image: ${GITLAB_DEPENDENCY_PROXY}ruby:2.7
   stage: review-prepare
   before_script:
     - source ./scripts/utils.sh

.gitlab/ci/setup.gitlab-ci.yml

@@ -52,7 +52,7 @@ no_ee_check:
 verify-tests-yml:
   extends:
     - .setup:rules:verify-tests-yml
-  image: ${GITLAB_DEPENDENCY_PROXY}ruby:2.7-alpine
+  image: ${GITLAB_DEPENDENCY_PROXY}ruby:2.7
   stage: test
   needs: []
   script: