ci: set lower resource requests for small jobs

We have a kubernetes cluster for x86_64 now to accept jobs. The default
limits are high to facilitate building packages.

For the smaller CI jobs like linting, these limits are too high and may
hinder other jobs from being accepted.

Set variables that set lower requests for these jobs.

.gitlab-ci.yml

@@ -7,6 +7,11 @@ variables:
   GIT_DEPTH: "500"
   REGISTRY: registry.alpinelinux.org
 
+.k8s-limits-small-job:
+  variables:
+    KUBERNETES_CPU_REQUEST: 2
+    KUBERNETES_MEMORY_REQUEST: 2Gi
+
 workflow:
   rules:
     - if: $CI_PIPELINE_SOURCE == "merge_request_event"
@@ -14,6 +19,7 @@ workflow:
     - if: $CI_COMMIT_TAG
 
 lint:
+  extends: [.k8s-limits-small-job]
   stage: verify
   image: $REGISTRY/alpine/infra/docker/apkbuild-lint-tools:latest
   interruptible: true
@@ -27,6 +33,7 @@ lint:
     - ci-fast
 
 generate-build-jobs:
+  extends: [.k8s-limits-small-job]
   stage: verify
   image:
     name: $REGISTRY/alpine/infra/docker/alpine-gitlab-ci:latest