ci(docs): Run all docs jobs on Kubernetes

docs/.gitlab-ci.yaml

@@ -20,6 +20,8 @@ pages:
   cache:
     paths:
       - $CARGO_HOME/bin
+  tags:
+    - kubernetes
 
 upload:
   stage: release
@@ -31,4 +33,6 @@ upload:
   script:
     - mc cp public gitops-docs
   rules:
-    - if: $CI_COMMIT_REF_NAME == $CI_DEFAULT_BRANCH
\ No newline at end of file
+    - if: $CI_COMMIT_REF_NAME == $CI_DEFAULT_BRANCH
+  tags:
+    - kubernetes
\ No newline at end of file