.github/workflows: auto-request k8s-devs review for Kubernetes/container paths (#20123)

Add a workflow that requests review from @tailscale/k8s-devs on PRs
touching Kubernetes operator, kube libraries, container build, etc.

Also cleans up check out code on k8s and dataplane workflow.

Updates #cleanup

Change-Id: I6fd7cacf71e1299f7e8f546ef52c4063fbf6bab8

Signed-off-by: Fernando Serboncini <fserb@tailscale.com>

.github/workflows/request-dataplane-review.yml

@@ -2,7 +2,7 @@ name: request-dataplane-review
 
 on:
   pull_request:
-    types: [ opened, synchronize, reopened, ready_for_review ]
+    types: [opened, synchronize, reopened, ready_for_review]
     paths:
       - ".github/workflows/request-dataplane-review.yml"
       - "**/*derp*"
@@ -15,8 +15,6 @@ jobs:
     name: Request Dataplane Review
     runs-on: ubuntu-latest
     steps:
-      - name: Check out code
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       - name: Get access token
         uses: actions/create-github-app-token@f8d387b68d61c58ab83c6c016672934102569859 # v3.0.0
         id: generate-token