ci: use generic tag for arch-independent jobs

This allows other fast runners to be used as well to run these jobs.

.gitlab-ci.yml

@@ -24,7 +24,7 @@ lint:
     - if: $CI_PIPELINE_SOURCE == "merge_request_event"
   tags:
     - docker-alpine
-    - x86_64
+    - ci-fast
 
 generate-build-jobs:
   stage: verify
@@ -37,7 +37,7 @@ generate-build-jobs:
       - .gitlab/build-jobs.yaml
   tags:
     - docker-alpine
-    - x86_64
+    - ci-fast
   rules:
     - if: $CI_PIPELINE_SOURCE == "merge_request_event"