gha: update to actions/checkout@v4

to resolve warning:
> Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: actions/checkout@v3.

.github/workflows/backport-command.yml

@@ -25,7 +25,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Get type of backport (issue or PR)
         env:
@@ -62,7 +62,7 @@ jobs:
       BACKPORT_BRANCH: ${{ needs.backport-type.outputs.backport_branch }}
     steps:
       - name: checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Get user
         env:
@@ -110,7 +110,7 @@ jobs:
           backport_commits=$(gh api "repos/$TARGET_FULL_REPO/pulls/$BACKPORT_PR_NUMBER/commits" --jq .[].sha | paste -s -d ' ' -)
           echo "backport_commits=$backport_commits" >> $GITHUB_OUTPUT
 
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         if: needs.backport-type.outputs.commented_on == 'pr'
         with:
           repository: ${{ steps.user.outputs.username }}/${{ steps.user.outputs.repo }}

.github/workflows/backport-on-merge.yml

@@ -17,7 +17,7 @@ jobs:
 
     steps:
       - name: checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       # Find the PR associated with this push, if there is one.
       - uses: jwalton/gh-find-current-pr@v1

.github/workflows/buildkite-slash-commands.yml

@@ -17,7 +17,7 @@ jobs:
   run-build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with: 
           repository: redpanda-data/sparse-checkout 
           token: ${{ secrets.ACTIONS_BOT_TOKEN }}

.github/workflows/cloud-installpack-bk-trigger.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with: 
           repository: redpanda-data/sparse-checkout 
           token: ${{ secrets.ACTIONS_BOT_TOKEN }}

.github/workflows/lint-cpp.yml

@@ -27,7 +27,7 @@ jobs:
     steps:
 
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Run clang-format
       run: |

.github/workflows/lint-includes.yml

@@ -15,6 +15,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: Run includes check
       run: python tools/lint-includes src/v

.github/workflows/lint-python.yml

@@ -19,7 +19,7 @@ jobs:
     steps:
 
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Install yapf
       run: pip install yapf==0.40.1

.github/workflows/lint-sh.yml

@@ -20,7 +20,7 @@ jobs:
     steps:
 
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Install shfmt
       env:

.github/workflows/rp-storage-tool-checks.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Install stable toolchain
         uses: actions-rs/toolchain@v1
         with:
@@ -36,7 +36,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Install stable toolchain
         uses: actions-rs/toolchain@v1