[buildbot] CI(deps): Bump actions/checkout from 4 to 5

[LEDE Commits]

ynezz pushed a commit to buildbot.git, branch main:
https://git.openwrt.org/54e80480d2cb1cd4f723d89addf65058b0e56709

commit 54e80480d2cb1cd4f723d89addf65058b0e56709
Author: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
AuthorDate: Tue Aug 12 04:55:28 2025 +0000

    CI(deps): Bump actions/checkout from 4 to 5
    
    Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 5.
    - [Release notes](https://github.com/actions/checkout/releases)
    - [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
    - [Commits](https://github.com/actions/checkout/compare/v4...v5)
    
    ---
    updated-dependencies:
    - dependency-name: actions/checkout
      dependency-version: '5'
      dependency-type: direct:production
      update-type: version-update:semver-major
    ...
    
    Signed-off-by: dependabot[bot] <support at github.com>
---
 .github/workflows/build-push.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/build-push.yml b/.github/workflows/build-push.yml
index e3c0be6..16b66e0 100644
--- a/.github/workflows/build-push.yml
+++ b/.github/workflows/build-push.yml
@@ -27,7 +27,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout at v4
+        uses: actions/checkout at v5
 
       - uses: actions/setup-python at v5
         with:
@@ -63,7 +63,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout at v4
+        uses: actions/checkout at v5
 
       - name: Environment variables
         run: |
@@ -105,7 +105,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout at v4
+        uses: actions/checkout at v5
 
       - name: Environment variables
         run: |