ci: Fix backend patterns in .gitlab/ci/rules.gitlab-ci.yml

Signed-off-by: Rémy Coutable <remy@rymai.me>

.gitlab/ci/rules.gitlab-ci.yml

@@ -247,7 +247,7 @@
   # List explicitly all the app/ dirs that are backend (i.e. all except app/assets).
   - "{,ee/,jh/}{app/channels,app/controllers,app/finders,app/graphql,app/helpers,app/mailers,app/models,app/policies,app/presenters,app/serializers,app/services,app/uploaders,app/validators,app/views,app/workers}/**/*"
   - "{,ee/,jh/}{bin,cable,config,db,generator_templates,lib}/**/*"
-  - "{,ee/,jh/}spec/**/*.rb"
+  - "{,ee/,jh/}spec/**/*"
   # CI changes
   - ".gitlab-ci.yml"
   - ".gitlab/ci/**/*"