ci: fix pull_request_target fork checkout refusal and Node 20 deprecation

    - bump the detect-changes checkout from v4 to the latest v7
      to clear the "Node 20 is deprecated" warning. It runs on
      Node 24.
    - actions/checkout now refuses to check out fork PR code from a
      pull_request_target workflow, which broke the trigger-jenkins
      job. It was checking out the fork's head SHA via
      'ref: github.event.pull_request.head.sha'.
      However, the job only forwards the github.event payload to
      Jenkins via curl.
    - paths-filter v3 runs on Node 20, which GitHub Actions runners
      now flag as deprecated. Update to v4 which runs on Node 24.

Fixes: 8e30ec80 ("ci: migrate Jenkins dispatch to pull_request_target")
Signed-off-by: Shubhika Garg <shubhika.garg@openairinterface.org>
Tested-by: Jaroslava Fiedlerova <jaroslava.fiedlerova@openairinterface.org>

.github/workflows/jenkins-dispatch.yml

@@ -88,11 +88,11 @@ jobs:
       protected_files_changed: ${{ steps.filter.outputs.protected }}
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
         with:
           fetch-depth: 0
       - name: Check changed files
-        uses: dorny/paths-filter@v3
+        uses: dorny/paths-filter@v4
         id: filter
         with:
           filters: |
@@ -136,10 +136,6 @@ jobs:
     runs-on: ubuntu-24.04
 
     steps:
-      - uses: actions/checkout@v4
-        with:
-          ref: ${{ github.event.pull_request.head.sha || github.ref }}
-
       - name: Trigger Jenkins
         run: |
           # Write payload to a temp file to avoid shell escaping issues