ci: checkout v5, concurrency cancel, dependabot for actions

.github/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"

.github/workflows/ci.yml

@@ -1,10 +1,13 @@
 name: ci
 on: [push, pull_request]
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
 jobs:
   host:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: host unit tests
         run: make -C tests clean && make -C tests test
       - name: ASan/UBSan
@@ -16,7 +19,7 @@ jobs:
   sdk-payload:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       # The release ZIP (v0.9) predates the SDK's 13.52 offsets, and the SDK's
       # crt/patch.c makes _start() terminate before main() for unlisted
       # firmware -- so a ZIP-built payload dies silently on 13.52. Build from

.github/workflows/release.yml

@@ -12,7 +12,7 @@ jobs:
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: checkout ps4-payload-sdk
         uses: actions/checkout@v4
         with: