[master] gha: various tweaks

.github/workflows/ci.yml

@@ -1,5 +1,18 @@
 name: ci
 
+# Default to 'contents: read', which grants actions to read commits.
+#
+# If any permission is set, any permission not included in the list is
+# implicitly set to "none".
+#
+# see https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#permissions
+permissions:
+  contents: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 on:
   workflow_dispatch:
   push:
@@ -13,6 +26,7 @@ on:
 jobs:
   build:
     runs-on: ubuntu-24.04
+    timeout-minutes: 60 # guardrails timeout for the whole job
     strategy:
       fail-fast: false
       matrix:
@@ -30,10 +44,10 @@ jobs:
     steps:
       -
         name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       -
         name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v1
+        uses: docker/setup-buildx-action@v3
       -
         name: Build
         run: |