Merge branch '42338-rubocop-cache' into 'master'

Cache rubocop cache for CI

Closes #42338

See merge request gitlab-org/gitlab-ce!16700

.gitlab-ci.yml

@@ -388,7 +388,6 @@ spinach-mysql 2 3: *spinach-metadata-mysql
 
 # Static analysis jobs
 .ruby-static-analysis: &ruby-static-analysis
-  <<: *pull-cache
   variables:
     SIMPLECOV: "false"
     SETUP_DB: "false"
@@ -409,6 +408,12 @@ static-analysis:
   stage: test
   script:
     - scripts/static-analysis
+  cache:
+    key: "ruby-2.3.6-with-yarn-and-rubocop"
+    paths:
+      - vendor/ruby
+      - .yarn-cache/
+      - tmp/rubocop_cache
 
 # Documentation checks:
 # - Check validity of relative links

.rubocop.yml

@@ -17,6 +17,7 @@ AllCops:
     - 'bin/**/*'
     - 'generator_templates/**/*'
     - 'builds/**/*'
+  CacheRootDirectory: tmp
 
 # Gitlab ###################################################################